This study aims to augment the D-lactic acid biosynthetic capacity of Lactobacillus delbrueckii subsp. bulgaricus ATCC 11842 through random mutagenesis. The mutant strain, Mut_N23, developed through synergistic application of ultraviolet (UV) irradiation and chemical mutagenesis using N-methyl-N′-nitro-N-nitrosoguanidine (NTG), exhibited 97% increase in D-lactic acid production and 37% enhancement in glucose uptake rate at flask level. Mut_N23 consistently produced optically pure D-lactic acid across seven generations, efficiently metabolizing lactose and sucrose to yield 4.47 g L^{− 1} and 3.38 g L^{− 1} of D-lactic acid, respectively. Optimal conditions identified through One-Factor-At-a-Time (OFAT), and Response Surface Methodology (RSM) facilitated maximum D-lactic acid concentration of 7.88 g L^{− 1} (300% increase) from lactose-MRS (deMan Rogosa Sharpe) with specific productivity of 0.110 g g^{− 1} h^{− 1}. When lactose was replaced with whey permeate as an application, 4.89 g L^{− 1} (140% increase) of D-lactic acid was obtained, with specific productivity of 0.066 g g^{− 1} h^{− 1} in lab-scale bioreactor setups, achieving 99.09% optical purity. Transcriptomics and enzymatic activity analyses substantiated enhanced performance of Mut_N23 signifying beneficial random mutations. Furthermore, characterization of purified D-lactic acid derived from whey permeate using Fourier Transform Infrared (FTIR) spectroscopy and proton Nuclear Magnetic Resonance (NMR) spectroscopy demonstrated parity with commercially available standards. This study highlights Mut_N23’s potential for efficient D-lactic acid production exploiting a spectrum of carbon sources, providing a foundation for future metabolic engineering to enhance biosynthetic productivity.

Cytochalasans are a class of hybrid polyketide-peptide natural products with diverse activities, including anti-tumor, anti-fungal, anti-parasitic, and anti-HIV properties, demonstrating significant application potential and broad market prospects. With the development of microbial metabolic engineering and synthetic biology, microbial synthesis of cytochalasans has emerged as a cost-effective and efficient alternative to traditional extraction and chemical synthesis methods, facilitating green and sustainable production. To better understand and promote the efficient heterologous biosynthesis of cytochalasans, this review systematically summarizes and discusses the research progress on the biosynthesis of cytochalasans. Firstly, an overview of the classification, application and biological activity of cytochalasans is provided. Subsequently, we systematically review the relevant gene clusters, enzymes, and biosynthetic pathways involved in the biosynthesis of cytochalasans. Additionally, the latest progress in the design of microbial cell factories for producing cytochalasans and the strategies to enhance their performance are summarized and discussed. Finally, the current challenges in developing efficient cell factories for producing cytochalasans with renewable biomass as a substrate and the corresponding strategies are proposed, aiming to achieve higher-efficiency green biomanufacturing of cytochalasans.

Human milk oligosaccharides (HMOs) are a crucial ingredient in mother’s milk for infant health. These are a structurally diverse group of soluble bioactive glycans having antiviral and anti-bacterial properties and promote the growth of probiotics, particularly Bifidobacteria. They modulate the immune system and are important for infant’s brain development. Not all infants are fortunate enough to receive mother milk, and rely on industrially produced infant formulas which lack HMOs. Thus, synthesizing HMOs through different methods is becoming more appealing form an industrial perspective. Despite huge efforts to obtain predominant HMOs through chemical, chemo-enzymatic, enzymatic, and whole-cell biotransformation of microorganisms, a limited number of HMOs could be produced in sufficient quantities due to lack of canonical enzymes that can add different metabolic pathways together to produce several HMO. Particularly, lacto-N-neotetraose and 2′-fucosyllactose are being added to infant formula and are well-tolerated by infants. Amide other methods, enzymatic and whole-cell biotransformation of microorganisms are promising approaches, but it requires intervention of innovative methodologies of synthetic biology. This review highlights innovative approaches, such as using plant system, and employing synthetic biology including redesigning of enzyme structure for producing HMOs at the industrial level. An interesting approach for synthesizing whole milk components in mammary cell lines is also mentioned.

Fruit wine is a widely accepted alcoholic beverage, which is favored by consumers because of its unique taste and rich nutrition. Acidity is a key determinant of fruit wine quality, which is closely related to the type and concentration of organic acids present in fruit wine. The optimum level of acidity effectively harmonizes the taste of the fruit wine and prevents deterioration; however, excessive acidity adversely affect the flavor profile. Understanding the common organic acids and deacidification methods in fruit wine has important guiding significance for wine making process. This paper reviews the main organic acids in fruit wine, including tartaric, citric, malic, and lactic acids, and discusses their influence on the sensory properties of fruit wine. Additionally, the traditional deacidification method and biotechnology deacidification method were described in detail, and the advantages and disadvantages of these methods and their practical application in the field of deacidification of fruit wine were evaluated, aiming at providing reference and guidance for the production of high quality fruit wine.

Keratin-rich by-products from the livestock industry, such as feathers, hair, and nails, present significant environmental challenges due to their resistance to degradation. Traditional disposal methods often exacerbate ecological issues, highlighting the need for more sustainable alternatives. This review explores innovative microbial bioconversion techniques using keratinolytic microorganisms to efficiently degrade keratin waste. These biological methods not only reduce environmental harm but also convert waste into valuable products, such as bioactive peptides and amino acids, which have applications in pharmaceuticals, cosmetics, agriculture, and even biofuels. The potential of microbial keratinases to revolutionize waste management by supporting a circular economy and promoting sustainability in various sectors. Moreover, the article explores keratin structure and the mechanisms of microbial degradation, focusing on the enzyme-driven processes that transform waste into high-value industrial products. Through a deeper understanding of these biological pathways, this study advocates for microbial bioconversion as a viable solution to current waste management challenges, offering significant industrial, environmental, and economic benefits.

Scientists are traditionally relied on bacteria to find and generate new natural chemicals. Gene editing research to identify, biosynthesize, and metabolically design natural chemicals is popular. The conventional genome editing relies on host or imported protein recombination. Microorganism’s diverse genetic history makes universal platforms difficult. The genetic variety renders experiments time consuming and useless. The CRISPR/Cas9 gene editing technique offers more functional diversity because to its diverse targeting capabilities, surpassing conventional approaches constrained by sequence homology or site restrictions. This enhances productivity, streamlines trials, and propels the research of natural goods. The CRISPR/Cas9 genetic editing technology may surpass sequence or location related constraints of earlier gene editing methods due to its targeting versatility. This methodology aids researchers investigating natural goods by optimizing and enhancing experimental techniques. This article provides an overview of the CRISPR/CRISPR-associated (Cas) mechanism, a transformative genome engineering technique in molecular biology. This paper aims to highlight and analyze the applications of CRISPR/Cas, particularly CRISPR/SpCas9, in genome editing for the identification of natural products. The creatures discussed embrace bacteria such as, Streptomyces, Bacillus, Clostridium, Corynebacterium, Myxobacteria and Escherichia. In a nutshell we will examine the potential benefits of using CRISPR/Cas in the discovery of natural products.

The increasing worldwide problem of food waste has a substantial impact on environmental contamination, requiring the implementation of efficient management strategies. Anaerobic digestion is a potential technology for managing food waste, which is frequently more sustainable than traditional disposal methods like incineration and composting. Anaerobic digestion not only reduces the negative effects on the environment but also enables the generation of useful by-products such as biofuels, biochemicals, and enzymes. This study underscores the importance of producing biofuel from food waste, specifically focusing on the process by which anaerobic microorganisms transform organic materials into biogas, predominantly consisting of methane (60-70%), carbon dioxide (30-40%), and small amounts of other gases. Given the biogas industry’s growing emphasis on energy generation, food waste is an excellent candidate for anaerobic digestion due to its substantial energy content and widespread availability. This review paper presents a new viewpoint by combining sophisticated microbial management with state-of-the-art biotechnology methods. It is trying to justify that the digestion process efficiency can be maximized by tackling operational issues and constraints affecting microbial performance. The study demonstrates that an optimal anaerobic digestion environment can be established by optimizing the digestive process in conjunction with integrated continuous surveillance diagnostic tools and biotechnological intervention. This innovative all-encompassing strategy is a solution to the common and practical challenges in anaerobic digestion of food waste, to utilize it as a resource for sustainable biogas generation.

Bifidobacterium animalis subsp. lactis 420 (B420), serving as a probiotic helping in metabolic health, has been extensively studied. Since the lipids produced by Bifidobacterium animalis subsp. lactis 420 (B420) exhibit variable bioactivities, understanding lipid profile alterations across different cultivation phases could offer valuable insights for developing targeted production strategies that enhance both the yield and bioactivity of specific lipid constituents. However, studies elucidating these lipid profile changes throughout various cultivation phases are limited, yet such research is essential for facilitating effective production strategies aimed at optimizing the yield and bioactivity of desired lipid components. Linoleic acid supplementation has been reported to enhance the production of unsaturated fatty acids in Bifidobacterium animalis subsp. lactis 420 (B420). This study aimed to reveal the lipidomics of B420 and its profile change during the cultivation. Using ultra-performance liquid chromatography/nano-electrospray ionization-tandem mass spectrometry, the investigation revealed a significantly diverse composition and relative intensity of lipids across different cultivation stages. A total of 862 lipids, categorized into 23 distinct lipid classes, were identified in B420. Among these, 683 unsaturated lipids comprised nearly 70% of the total lipid pool. Following linoleic acid supplementation, the total number of identified lipid compounds increased to 891, with unsaturated lipids rising to 701, which included 509 polyunsaturated lipids. Additionally, the relative content of unsaturated lipids at each growth phase demonstrated a significant increase, peaking at 75.69% during the late stationary phase, which is 8.89% higher than observed in the absence of linoleic acid supplementation. The intensity of unsaturated fatty acyls increased to 13.55 times. Notably, linoleic acid induced the production of unsaturated lipids characterized by varying numbers and distributions of double bonds. For the first time, this study enhances our understanding of the lipid profile changes in B420 and reveals the compositional and quantitative variations of unsaturated lipids resulting from linoleic acid supplementation during cultivation. Our research provided a new understanding of the probiotic effects of B420 from a lipidomic perspective and elucidate the mechanisms underlying linoleic acid supplementation during cultivation.

Squalene, a long-chain unsaturated triterpene compound, finds extensive applications in the food, pharmaceutical, and cosmetic industries owing to its distinctive molecular structure. Traditional methods of squalene production involve extraction from shark liver and plant oils, practices that are neither environmentally sustainable nor economically viable. In light of these challenges, microbial biosynthesis has emerged as a promising alternative, offering significant environmental and economic benefits. In this study, a combinatorial metabolic engineering approach was utilized to modify Saccharomyces cerevisiae for the efficient biosynthesis of squalene. Firstly, by introducing an exogenous NADH-dependent HMGR and enhancing the endogenous synthesis pathways, resulting in a squalene titer of 56.5 mg/L. Subsequently, by integrating the mevalonate synthesis pathway into the mitochondria and introducing the ethanol utilization pathway, the supply of precursors for squalene synthesis was enhanced, resulting in a significant increase in the squalene titer to 312.5 mg/L. Furthermore, the native promoter of ERG1 gene was engineered to reduce the flux through the ergosterol biosynthesis pathway. Following optimization of the culture medium, the squalene titer of the engineered strain was improved to 595 mg/L in shake flasks and 1929.7 mg/L in 5 L fermenters, respectively. This research provides valuable insights into the metabolic engineering of microorganisms for enhanced squalene production.

L-Methionine is widely used in food, agricultural and pharmaceutical industries. In this study, the L-methionine production in Corynebacterium glutamicum ATCC13032 was promoted by eliminating the feedback inhibition of key rate-limiting enzymes, blocking L-threonine biosynthesis, and strengthening the downstream pathway of L-homoserine. ATCC13032 does not accumulate L-threonine, we found that overexpressing the genes lysC and hom^G378S could accumulate 0.6 g/L L-threonine. Deleting the genes thrB, McbR, and metD in ATCC13032 could accumulate 0.49 g/L L-methionine. Next, enhancing oxaloacetate supply, overexpressing brnFE, and deleting Ncgl2640 that involved in the repression of sulphuric metabolism could accumulate 0.92 g/L L-methionine. Further overexpressing the genes related to L-homoserine downstream pathway, the resulting strain ZBW011/pEC-metYX could produce 1.82 g/L L-methionine. Finally, the gene pyk2 was deleted and the final strain ZBW014/pEC-metYX produced 7.06 g/L L-methionine in a 2.4-L fermenter. The strategies presented in this study would be useful to engineer C. glutamicum for industrial L-methionine production.

Itaconic acid (ITA) is an unsaturated organic acid used in industrial production due to its versatility as a polymer building block. Engineering microbial cell factories for ITA biosynthesis from cost-effective and renewable raw materials has gained significant attention. Here, we performed combinatorial engineering using Saccharomyces cerevisiae to improve ITA production. First, exogenous cis-aconitic acid decarboxylase (CAD) was integrated into S. cerevisiae to construct the ITA-producing chassis. Then, the rate-limiting step was eliminated by changing the promoter that drives CAD expression to optimize ITA synthesis. A mitochondrial cis-aconitate transporter MTTA was also expressed to facilitate the transport of precursor, which resulted in an ITA titer of 244 mg/L. Furthermore, with overexpression of truncated citrate synthase tCIT2, an increased titer of 409 mg/L was obtained. Finally, the transport protein Qdr3 was overexpressed to enhance the export of ITA, resulting in a production of 578 mg/L in shake flask. In a 5-L bioreactor, the ITA titer reached 1.2 g/L, representing the highest reported level in S. cerevisiae. Overall, an advanced recombinant yeast strain was constructed for the efficient production of ITA via combinatorial metabolic engineering.

L-tryptophan is an essential aromatic amino acid, which is also a precursor for the synthesis of multiple important bioactive compounds and is widely used in food additives, medicine and animal feed. There are many studies on the synthesis of L-tryptophan by microbial cell factories; however, further development has been limited by problems such as low conversion rates from glucose to L-tryptophan and dependence on antibiotics and inducers during the fermentation process. In this study, to enhance the L-tryptophan synthesis level for increasing demands, combinations of feedback-resistant enzymes AroG, TrpE and SerA were optimized, 13 synthesis-related genes (including ppsA, yddG and etc.) were overexpressed. And then the optimized aroG^S211F, trpE^{Q71K/S94N/C465Y}-trpABCD and serA^H344A/N364A expression cassette was integrated into the genome with the CRISPR-associated transposases system. The copy numbers of the expression cassette were optimized to balance the cell growth and L-tryptophan synthesis, yielding a producing strain without plasmids. To further optimize carbon flux and facilitate L-tryptophan biosynthesis, the yddG and prs^L135I was knocked in, and poxB was knocked out with CRISPR-Cas9 system. Finally, the accumulation of L-tryptophan reached 5.1 g/L in shake flask culture for 48 h, the total L-tryptophan production of the optimal strain reached 43.0 g/L (extracellular production was 30.9 g/L) under conditions of no antibiotics, inducers and other extra addition at 35 h in a 3 L bioreactor, and the total conversion rate reached 0.180 g L-tryptophan/g glucose.

Tannase has vital importance in several industries. However, tannase production employing tannic acid as a substrate is costly. This study optimized medium components, concentration of medium components and physical parameters to yield maximum tannase production from Bacillus licheniformis AS1 in submerged fermentation utilizing low-cost agri-waste Citrus limetta (Mosambi) peels as a substrate. Tannase activity and stability parameters were also optimized. The produced crude tannase and partially purified tannase were used to reduce the bitterness (tannin content) from pomegranate juice and to remove the dye. B. licheniformis AS1 produced 0.361 U/mL under un-optimized conditions. During screening of medium components, Mosambi peels, yeast extract, potassium nitrate and sodium chloride was selected. The concentration of medium components (0.8% Mosambi peels, 0.2% yeast extract, 0.12% potassium nitrate, and 0.06% sodium chloride) was optimized using central composite design which yielded tannase up to 27.809 U/mL. Then, physical conditions were optimized (agitation, 100 µl inoculum size, 40 °C temperature, pH 3, and 72 h of incubation) and yielded tannase up to 43.83 ± 0.82 U/mL. The optimal conditions for tannase activity appeared at pH 8, at 40 °C, and 10 min incubation period with 0.3% substrate concentration. The tannase showed highest stability at 40 ºC and at pH 7. The maximum partial purified tannase activity was recorded at pH 8 and at 40 °C, while enzyme stability was at pH 7 and a temperature of 40 °C. The reduction in tannin content of pomegranate juice was noted after 2 h incubation at 37 ºC. This enzyme was also effective for the partial removal of crystal violet dye. The tannase produced in this study was cost-effective due to utilization of low cost agri-waste and showed potential in various industrial applications.

Yeast single cell protein (SCP) is a nutritious protein supplement of artificial feed and food. It is expected that yeast cells grow on nonfood feedstocks instead of agricultural sugars for synthesizing high-quality proteins. Herein, the protein content and quality of the edible yeast Candida utilis were investigated on utilizing ability of carbon and nitrogen sources. We found that dihydroxyacetone (DHA), a feedstock that can be chemically or enzymatically generated from one-carbon (C1) compounds such as methane, methanol and even CO₂, was comparable with glucose but superior to acetate for C. utilis protein production. The essential amino acid score (EAAS) of DHA-cultured C. utilis protein not only met FAO/WHO (2013) standard, but also surpassed that of benchmark soybean and fish feed. Fed-batch fermentation of C. utilis utilizing DHA feedstock in a 5 L fermenter performed a growth rate of 1.3 g DCW L⁻¹ h⁻¹ and a total of 34.8 g L⁻¹ biomass with the protein content of 60.1% DW, validating scale-up production. This work highlights that C. utilis SCP derived from low-carbon source is a high-quality protein for advancing sustainable feed and food supply.

Sauce-flavor Baijiu, a traditional Chinese liquor with deep cultural and economic value, derives its unique aroma from microbial metabolic activities. However, low pyrazine content limits its functional properties and market competitiveness. In this research, a multi-omics approach was employed to investigate the succession patterns of microorganisms during the fermentation process of sauce flavor Baijiu. Concurrently, the dynamic variations of pyrazines and other flavor-contributing compounds were analyzed. By integrating core microorganisms’ abundance, flavor-producing potential, and interaction patterns, we constructed a synthetic microbial community. This community is composed of Pichia kudriavzevii, Saccharomyces cereviceae, Zygosaccharomyces bailii, Schizosaccharomyces pombe, Lactobacillus acetotolerans, Bacillus amyloliquefaciens, and Bacillus subtilis. Synthetic microbial community inoculation increased total pyrazines by 2.1-fold (P < 0.01) and esters by 35%, with sensory evaluations confirming enhanced ‘sauce aroma’ and ‘lingering fragrance.’ This work has constructed a synthetic microbial community for enhancing pyrazines metabolism in sauce-flavor Baijiu. This construction of the synthetic microbial community provides a novel and effective strategy for enhancing the quality of sauce flavor Baijiu, thereby playing a pivotal role in promoting the optimization and development of the sauce flavor Baijiu production process. Moreover, this strategy offers a novel paradigm for precision modulation of traditional fermented foods.

As a vital microorganism during Huangjiu fermentation, fungi have not been thoroughly evaluated for their potential relationship with total purine levels in Huangjiu, which is a major contributing factor to hyperuricemia (HUA) and gout. In this study, we revealed the correlation between the succession of fungal communities and total purine content during Huangjiu fermentation. Our results demonstrated a continuous increase in total purine content during fermentation, rising from 13.08 to 72.12 mg/L. We observed significant dynamic changes in fungal community composition and diversity throughout the fermentation process, with the highest fungal species richness occurring on the third day. At the phylum level, Ascomycota dominated throughout fermentation (92.5–97.4%). At the genus level, the predominant taxa were Aspergillus (42.5–73.5%), Saccharomyces (0.0–41.1%), and Paecilomyces (0.0–16.9%), with Aspergillus dominating during the initial phase (0–3 days) and Saccharomyces becoming predominant in later stages (6–18 days). Correlation analysis revealed that Saccharomyces cerevisiae showed a strong positive correlation with total purine levels (r = 0.73), while Aspergillus intermedius (r = − 0.79) and Aspergillus flavus (r = − 0.70) exhibited significant negative correlations. Furthermore, we identified that predominant fungal genera participate in purine metabolism. This study enhances our scientific understanding of purine formation mechanisms in Huangjiu and provides a foundation for developing targeted strategies to regulate purine content in future industrial production.

Laccases are extensively studied by researchers because they can efficiently catalyze phenolic and non-phenolic compounds, as well as extremely recalcitrant environmental pollutants such as textile dyes. Between all carriers available for enzymatic immobilization, magnetic nanoparticles have the advantage of easy bioseparation by an external magnetic field from the reaction medium. Cobalt ferrite magnetic nanoparticles were synthesized and functionalized to immobilize laccases produced by Phlebia brevispora BAFC 633. The functionalization was made with 3-aminopropyltriethoxysilane followed by glutaraldehyde. The biocatalyst was employed to bioremove thymol blue from an aqueous solution. Magnetic nanoparticles were characterized by FTIR, TEM, DRX and magnetism, before and after immobilization. Immobilized laccases removed 86% of thymol blue in 23 h, and showed the same bioremoval capability even 3 cycles. The Michaelis-Menten constant was determinate, and immobilized laccases exhibit higher affinity to thymol blue and 2,6-dimethoxyphenol than free laccases. Regarding stability, immobilized laccases kept 78% of activity at 28 days while it was maintained in the refrigerator against free laccases, which reached 63% of initial activity at 28 days under the same conditions. The effective concentration 50 from Lactuca sativa was near 100% when the effluent was diluted at least 1:1 in water. Thus, the biocatalyst obtained has a potential approach in the bioremoval and detoxification of dyes such as thymol blue.

Corynebacterium glutamicum is a safe strain with great potential for industrial applications, but more research is needed on secretory expression systems. Here, we constructed a non-inducible secretory expression system of the strain. By building a signal peptide library, we screened several Sce-type signal peptides and analyzed the relationship between their constitutive properties and secretory efficiency. To further meet the safety requirements in industrial applications, fifteen constitutive promoters were screened, and protein expression was optimized by promoter tandem strategy. In the WYJ1, WYJ2, WYJ3, and WYJ4 engineering strains, we confirmed that the modification of cell permeability favored protein secretion. The engineering strains WYJ2P35SP35 and WYJ4P35SP35 were scaled up for culture, and their extracellular enzyme activities and proteins reached 26.42 U/mL and 19.65 mg/L, and 23.97 U/mL and 13.84 mg/L, respectively. This secretory expression system increases the potential of industrial applications of Corynebacterium glutamicum and lays the foundation for applications.

Among the 16 prioritized polycyclic aromatic hydrocarbons (PAHs), naphthalene, phenanthrene, fluoranthene, and pyrene have been used for bacterial degradation study. From the free-air CO₂ enriched (FACE) soil, five Bacillus strains were isolated and used to utilize the four model toxicants at different concentrations as the sole carbon source. Bacillus amyloliquefaciens has great resistance to different PAHs and better degradation capability. B. amyloliquefaciens can degrade naphthalene (0.5 mg mL^− 1), fluoranthene (0.1 mg mL^− 1), and pyrene (0.1 mg mL^− 1) up to 94%, 65%, and 56% respectively, while B. cereus mineralized phenanthrene (0.5 mg mL^− 1) up to 71% within seven days of incubation. B amyloliquefaciens and B. cereus have the capability of ring cleavage and they can convert PAH compounds into less toxic compounds. Based on the metabolites obtained through GC-MS, the biodegradation pathways for each PAH have been predicted to end up in the tricarboxylic acid cycle.

An automated system for the real-time measurement and control of the optical density of the microalga Tetraselmis viridis and cyanobacterium Limnospira platensis has been developed based on the open-source Arduino Nano electronics platform. The system consists of a main unit, an optical density sensor, a relay unit, a temperature sensor, and associated software. The optical density sensor consists of light diodes (with a maximum emission spectrum in the infrared region at 940 nm) as a light source and photodiodes as receivers; the culture density is estimated based on the attenuation of radiation passing through it. The proposed method exhibited high accuracy (R² = 0.995, with root mean square error being approximately 0.1 g L⁻¹) in a wide range of biomass concentrations, from 0.27 to 0.97 g L⁻¹ for T. viridis and from 0.035 to 1.25 g L⁻¹ for L. platensis. The registered biomass productivity at the linear stage of batch cultivation reached 0.15 g L⁻¹ day⁻¹ for T. viridis and 0.17 g L⁻¹ day⁻¹ for L. platensis. The sensor readings were found to be dependent on air temperature, with a coefficient of 0.0136 V/°C. This suggests that the system has the potential for use in a changing outdoor environment, provided that temperature correction is applied during calculations. Furthermore, the measuring system does not require sampling from the photobioreactor or dilution of high cell concentrations prior to measuring dense microalgae cultures. This eliminates the risk of dilution error and contamination. The experimental application of the system for the studied species demonstrated its potential for use with microalgae species exhibiting diverse pigment compositions, including those prone to sedimentation and filamentous forms.

Anaerobic digestion (AD) systems generate biogas from protein-rich waste, with certain anaerobes modulating gene regulatory networks (GRNs) to manage ammonia toxicity. This study reconstructs GRN models for five key anaerobes—a hyper-ammonia-producing anaerobe Acetoanaerobium sticklandii H1, an anaerobic sulfur-reducing bacterium Desulfovibrio vulgaris Hildenborough, a hydrogenotrophic methanogen Methanothermobacter thermautotrophicus ΔH, a heterotrophic methanogen Methanosarcina mazei Gö1, and a methylotrophic methanogen Methanoculleus bourgensis MS2T—using genome-wide data to understand their metabolic regulation in AD processes. These GRNs integrate gene regulatory elements, thereby revealing species-specific adaptations that facilitate ammonia tolerance, substrate metabolism, and methane production. Regulatory elements, such as ExsA, PtxR, and GadW, influence pathways for carbon, nitrogen, and energy metabolism. A. sticklandii and M. mazei were crucial for carbon source utilization, whereas M. bourgensis adapted to ammonium-rich conditions without a typical ammonium uptake system. The results of our study provide insights into the metabolic interactions and regulatory roles within biogas-producing communities. This work proposes a framework for designing synthetic microbial communities to enhance biomethane yield from protein-based substrates, supporting AD efficiency improvements.

Agricultural wastes are characterized by bioactive compounds that can be used to produce different byproducts, including enzymes, which are obtained through solid state fermentation (SSF). The goal of this study was to evaluate the initial pH and moisture conditions of a substrate composed of carrot peels and corn husk residues (tusa) by SSF to obtain cellulase enzymes. Carrot and corn wastes were characterized to determine their physicochemical properties, confirming their suitability for the fermentation process. It was found that endoglucanase enzyme activity increased with time and was favored at a humidity of 75% and a pH of 5.2, reaching values above 300 U/mg protein. However, no significant trends were observed in exocellulase activity related to the study´s factors. Although the use of agro-industrial wastes to obtain high-value molecules has been widely studied, combining carrot and corn wastes as a substrate for cellulase production using Cladosporium sp. _V3 (GenBank No. PP931187) isolated from pineapple wastes has been poorly characterized.

Laccase is an enzyme rich in copper and abundantly present in white rot fungus Trametes versicolor, which can degrade a wide range of pharmaceutical compounds from wastewater that conventional treatment methods cannot fully remove. In this paper, we performed molecular docking studies on laccase (Pdb id: 1GYC) with 10 selected pharmaceutical compounds (2,2′-azino-bis- (3-ethylbenzothiazoline-6-sulfonic) acid (ABTS) taken as control, carbamazepine, tetracycline, indomethacin, fenoprofen, celiprolol, metoprolol, diclofenac, sulfisoxazole, sulfapyridine) commonly present in wastewater. The study aims to understand the binding interaction and stability of enzyme-substrate complex to mediate the bioremediation of these pharmaceutical pollutants from wastewater. Docking analysis was performed using the Maestro Schrödinger suite. The result revealed a significant binding affinity of laccase with pharmaceutical pollutants ranging from − 5 to − 6 Kcal mol⁻¹. Further, the 2-D analysis of ligands and polar amino acid residues unravels the involvement of hydrophobic interactions and stability of enzyme-substrate complexes. The study suggested an effective laccase-mediated bioremediation method for wastewater treatment.

A simple and robust reversed-phase high performance liquid chromatography procedure was developed with only an aqueous H₃PO₄ solution (pH 2.1) as the mobile phase for the simultaneous determination of nine organic acids (oxalic, formic, malic, lactic, acetic, citric, succinic, fumaric, and gallic acids) in beer based on a polar-copolymerized 3-chloropropyl C18 column. The proposed method was validated according to linearity, limits of detection, accuracy, precision, repeatability, and reproducibility. Quantifications of the nine organic acids in 12 commercial Chinese beer samples from five different brands were conducted only after degassing and filtration of the samples. In all beer samples, the most abundant organic acid was succinic acid; its concentration was in the range of 907.99–3557.22 mg/L. This was followed by malic acid (170.39–936.78 mg/L). Principal component analysis was used to compare the different brand of beers according to organic acid concentration, and results may provide a reference for the evaluation of beer quality and taste.