Interest in the technology for producing alternative proteins is rapidly increasing, driven by the need to find new ways to produce and consume protein for the global population. This technology involves growing different microorganisms and animal cells under controlled conditions to ensure their viability and efficient growth. The cultivation process takes place in different types of bioreactors, from traditional models to innovative new designs, each offering unique features and capabilities. The most commonly used bioreactors are stirred tank reactors, which are mechanically agitated, and airlift or bubble column bioreactors, which are pneumatically agitated. These bioreactors are often adapted or modified to optimize the production of cultured meat. Essential to the process are microcarriers or scaffolds that support cell adhesion and proliferation. Other bioreactor models, such as hollow fiber and packed bed bioreactors, are also being explored. The trend towards single-use technology is growing due to benefits like easier cleaning and sterilization, and reduced operation times, though it does raise concerns about plastic waste. This review not only describes various bioreactor models but also discusses instrumentation and control systems. It aims to present the main bioreactor models currently in use for cultivated meat production, detailing their features, advantages, disadvantages, and the technological challenges that need to be addressed.
There is a growing worldwide demand for biopesticides based on fungal conidia produced in solid-state culture bioreactors. Packed bed column bioreactors (PBCBs) have gained prominence due to their high productivity. In traditional PBCBs, scaling up by increasing the bioreactor diameter is considered an effective strategy. However, this approach presents challenges as the bed porosity diminishes, impeding mycelium propagation, gas exchange, and heat removal. Therefore, this study introduces a novel PBCB design to improve the solid matrix structure for conidia production from Trichoderma harzianum and Metarhizium robertsii. The proposed PBCB design incorporates channelled internal cylinders (ChICs) to elevate the ratio between the wall surface (WS) in contact with the substrate and the working volume (Wv). The conidia production obtained in 28 cm diameter PBCB with ChIC versus that reached in conventional 2.5 cm diameter PBCB were compared to evaluate the effectiveness of design for the diameter increase. The results demonstrate that increasing the WS: Wv ratio significantly enhances porosity, facilitating an almost 172-fold increase in the working volume for conidia production from T. harzianum and M. robertsii without compromising microbial growth or conidia volumetric production (> 6 × 108 conidia cm− 3). This underscores the effectiveness of adjusting the WS: Wv ratio as a viable strategy for increasing diameter. Incorporating channelled internal cylinders into packed column bed bioreactors enables the expansion of the bioreactor diameter for conidia production from T. harzianum and M. robertsii. This innovative approach should be explored for its potential application in obtaining biomass, enzymes, and metabolites from other microorganisms.
Bacteroides thetaiotaomicron colonizes the human gastrointestinal tract and establishes a symbiotic relationship with the host, contributing to reducing intestinal inflammation and enhancing resistance against foreign pathogens. Recent reports have revealed that diverse lipid species such as glycerophospholipids, sphingolipids, and N-acyl amines exist in B. thetaiotaomicron and play essential roles in the immune process. In this research, total lipids obtained from B. thetaiotaomicron were purified via thin-layer chromatography, and the species and molecular structures of visible lipids in different hydrophobic regions were qualitatively characterized by high-performance liquid chromatography-mass spectrometry. The results indicated that seven lipid species were primarily displayed on the plate, including phosphatidylethanolamine, ethanolamine phosphoryl dihydroceramide, inositol phosphoryl dihydroceramide, glycyl-serine phosphoryl dihydroceramide, phosphatidylglycerol, cardiolipin, and glycyl-serine phosphoryl diacylglycerol. The phosphatidylethanolamine, ethanolamine phosphoryl dihydroceramide, and inositol phosphoryl dihydroceramide species corresponding to ion peaks at m/z 676.48, 691.53, and 796.53 exhibited significantly high abundance compared to other species, suggesting their prevalent presence in total lipids. The molecular structures of phosphatidylethanolamine and ethanolamine phosphoryl dihydroceramide were derived from the modification of diacylglycerol and dihydroceramide with phosphoethanolamine, while the structure of inositol phosphoryl dihydroceramide was derived from the modification of dihydroceramide with phosphoinositol. The phosphatidylglycerol and cardiolipin species corresponding to m/z 721.51 and 1323.94 have been detected in the membrane lipids of B. thetaiotaomicron, although they were not mentioned in previous studies. These findings are important for understanding the molecular mechanisms of B. thetaiotaomicron colonization in mammalian gut.
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 homG378S 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.
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.
The present study was conducted to explore the growth dynamics and nutraceutical potential of the diatom Nitzschia sp. isolated from a freshwater sample collected from Uttarakhand, India, which is a high-altitude environment. This aspect is particularly noteworthy because high-altitude diatoms are subject to unique environmental conditions that can influence their biochemical and metabolic activities and this aspects were rarely studied in diatoms. The highest biomass productivity attained was 0.5 mg mL−1 when the culture was grown for 15 days. The biochemical protein content was measured as 15.7 mg g−1, carbohydrate content as 76.6 mg g−1, and total chlorophyll content was 87.3 mg g−1. Secondary metabolite screening shows the total flavonoid content as 0.63 mg g−1 and tocopherol content as 0.60 mg g−1. The fatty acid profile shows the monounsaturated fatty acids (MUFA) to be the highest at 56.37%. This study demonstrates the adaptability of diatoms and could offer a helpful vision for future species-specific selection for the mass production of metabolites with potential health benefits, such as fucoxanthin (Fx), docosahexaenoic acid (DHA), and eicosapentaenoic acid (EPA).
The production of L-alanine was enhanced in Corynebacterium glutamicum ATCC13869 through metabolic engineering of the biosynthesis pathways of L-alanine and fatty acids. Strains ΔfasB, ΔfasBR, ΔfasBΔpks13 and ΔfasBRΔpks13 were constructed and exhibited increased L-alanine yields up to 17.29 g/L. Different from ΔfasB mutant constructed from C. glutamicum ATCC13032 in which L-glutamate production accumulated, the muatnt ΔfasB constructed from C. glutamicum ATCC13869 in this study significantly produce L-alanine without L-glutamate accumulation. Transcriptional level analysis revealed that the knockout of fasB upregulated the expression levels of the genes related to L-alanine synthesis but downregulated those associated with fatty acid synthesis, confirming the redirection of metabolic flux from fatty acid synthesis to L-alanine synthesis in these strains. L-alanine productions were further enhanced in strains ΔfasB and ΔfasBR through the combinatorial expression of heterologous genes Bacillus subtilis alaD encoding alanine dehydrogenase and Escherichia coli alaE encoding alanine export protein, and the yields reached 55.21 g/L and 54.95 g/L, respectively. Finally, 69.9 g/L L-alanine was obtained in ΔfasB/pJYW-5-alaDE after 60 h of fermentation by supplementing glucose. Our data indicate that disrupting the fatty acid biosynthesis could redirect metabolic flux towards L-alanine biosynthesis. These results provide a new strategy for increasing the production of L-alanine in C. glutamicum.
Microalgae and cyanobacteria are photosynthetic microorganisms that inhabit freshwater and marine ecosystems. Bioactive substances (metabolites such as astaxanthin, chlorophyll-a, and phycobiliproteins) obtained from microalgae and cyanobacteria are used in a multitude of fields. Phycobiliproteins are photosynthetic antenna pigments that are found in cyanobacteria, red algae, and cryptophytes. This study aimed to determine the optimal parameters for phycobiliprotein extraction from lyophilized cells obtained from a triple algal co-culture. These parameters included the biomass: solvent ratio, CaCI2 concentration, agitation speed, and extraction time. In all optimization processes, phycocyanin is observed to be the most dominant, while phycoerythrin has the lowest amount. It is demonstrated that all phycobiliprotein efficiencies increase after each optimization process. The highest yield of 12.51 ± 0.23 mg phycobiliprotein/g freeze-dried weight was obtained using a 1:100 (v: v) biomass: solvent ratio with 2% CaCl₂ at 100 rpm for 1 h. The significance of carefully controlling extraction parameters to maximize the efficiency of PBP extraction from triple algal co-culture is highlighted by these results. Employing a combination of extraction methods could potentially improve both the yield and purity of phycobiliproteins obtained from a triple algal co-culture. Future research should focus on developing and refining scaling-up techniques to enhance and optimize the extraction process of phycobiliproteins for industrial use.
Buildings contribute around 37% to global carbon emissions, prompting a growing interest in innovative carbon capture technologies. Among these, the integration of microalgae-based photosynthesis into building facades has emerged as a promising solution. This approach offers multiple benefits, including carbon sequestration, reduced energy consumption, dynamic shading, and improved thermal regulation. This paper investigates the impact of integrating photobioreactor (PBR) facade elements, specifically on the south-facing facade of an office building in a temperate continental climate. The study evaluates the system’s effects on indoor thermal and visual comfort, energy production, and carbon dioxide (CO2) sequestration for three distinct PBR facade alternatives and compares them with a commercial curtain wall. The continuous PBR system varies in performance depending on production intensity, necessitating an initial optimization for thermal and visual comfort alongside energy use. Simulations were conducted using Rhinoceros/Grasshopper plug-ins, with optimization performed via the Octopus tool. The results, focusing on the Chlorella vulgaris algae strain, demonstrate that all facade configurations achieve a daylight performance exceeding 50% and meet desired thermal comfort levels. Although the energy generated by the PBR facade does not fully offset the building’s energy consumption, annual CO2 sequestration ranges from 84.87 kg to 770.13 kg. This study concludes that microalgae facades offer a viable strategy for enhancing a building’s energy performance and reducing CO2 emissions, without compromising occupant comfort. Additionally, the findings provide valuable insights for designers, researchers, investors and stakeholders and provides a payback period of these systems (16–24 years) for commercialization in the building industry.
The expanding field of alternative proteins represents a transformative approach to addressing global food security and sustainability challenges. Among these, fermentation-derived alternative proteins cultivated from microorganisms such as fungi, bacteria, and algae offer a promising avenue for sustainable protein production. This review explores the selection and utilization of raw materials to produce microbial proteins through fermentation processes. Critical raw materials include agricultural byproducts, industrial waste streams, and specifically designed feedstocks, which not only mitigate environmental footprint but also enhance the economic viability of production systems. The utilization of lignocellulosic biomass and molasses has demonstrated considerable promise, attributed to their abundant and renewable nature. The review underscored the necessity of exploring specific areas to enhance the viability of producing microbial protein from diverse raw materials. These areas include improving pre-treatment strategies to enhance substrate suitability for fermentation, optimizing fermentation processes for increased yield and reduced costs, and developing more resilient microorganisms capable of thriving on varied substrates. These strategies are crucial for advancing the production of alternative proteins through fermentation, in addition to raw material selection, which is vital in the scalability and sustainability of alternative protein production through fermentation, emphasizing the need for continued research and innovation in this field.