Nanobiotechnology has revolutionized material synthesis by harnessing biological systems for the production of eco-friendly nanoparticles. This review examines the role of diatoms, a unique type of microalgae characterized by intricate biosilica-based frustules, as natural nanofactories for synthesizing nanostructured materials. The review provides an overview of green synthesis methods, emphasizing the advantages of biological routes, specifically microbial, plant-based, and algal systems, over conventional physical and chemical approaches. A dedicated focus on diatom-mediated nanoparticle synthesis highlights the role of frustules as nanostructured templates, the mechanisms of intracellular and extracellular synthesis, and the influence of factors such as pH, precursors, and light. Advances in genetically engineered and functionalized diatoms are discussed alongside recent innovations. The review further details their biomedical applications, encompassing antimicrobial and anticancer activities, drug delivery platforms, and biosensing/bioimaging. Finally, it addresses challenges in scalability, standardization, and future trends, including engineered frustules and hybrid nanomaterials, offering a comprehensive outlook on diatom-based nanotechnology for biomedical advancements.

1,3-propanediol (1,3-PDO) is an important monomer for polyester production with broad industrial applications. Klebsiella pneumoniae is currently recognized as a highly efficient producer of 1,3-PDO. However, the higher cost of glycerol substrate compared with glucose limits the economic feasibility of this route. In the present study, the K. pneumoniae strain FMME-KP was extensively engineered for efficient 1,3-PDO production from glucose. Strategies included the introduction of a glycerol synthetic pathway from glucose, balancing carbon distribution between biomass formation and product synthesis, alleviating carbon catabolite repression, and strengthening the 1,3-PDO biosynthetic route. The optimized strain, K. pneumoniae GZ31, produced 84.7 g/L of 1,3-PDO, achieving a yield of 0.51 g/g and a productivity of 1.74 g/L/h.

Lignin recovery from lignocellulosic material is a prominent solution to environmental concerns and problems and establishes more sustainable and competitive lignocellulosic biorefineries. Lignin has the potential to produce various commodity chemicals, biofuels, plastics, dyes, adhesives, concrete binders, foaming agents, lubricants, and nanomaterials, and is a commitment step for a safer and sustainable circular bioeconomy development. However, lignin valorization is hindered by a series of factors, i.e., heterogeneous nature, intrinsic recalcitrance, and the presence of strong intermolecular bonding and functionalities. Most of the lignin residue generated during cellulosic or pulp industries is combusted for electricity production in an uneconomic manner. Therefore, we have critically assessed and discussed the main constraints of novel strategies concerning lignin isolation and valorization, which is widely used in the landscape of lignocellulose biomass-based biorefining to reduce the dependency on fossil reserves and indirectly impacts the circular economy and lifestyle of people. Finally, this review highlights the integrated approach linked to enzyme-to-microbe, microbe-to-microbe interactions, or modified lignin fraction via employing metabolic engineering, discusses the commercial aspects of lignin in the market, and describes the future perspectives as well. Additionally, various advanced catalytic approaches under oxidative/reductive environments and hydrodeoxygenation are well explored, illustrating their influence on the selectivity of lignin depolymerization. The article will consolidate existing knowledge but also incorporate some novel perspectives for future advancement concerning lignin valorization in a sustainable way, which is a prerequisite objective for various biorefinery developments.

Dairy-derived carbohydrates are traditionally used as prebiotics; however, considering allergies, intolerance, and vegan lifestyles, plant-based prebiotics are being explored. This study investigated the prebiotic effects of banana fruit, oats grain and chicory root powders on indigenous lactic acid bacteria with the aim to develop a synbiotic instant mix that offers therapeutic benefits. It was seen that the water binding capacity was highest in banan fruit powder while Oat grain powder had the highest oil binding capacity. Chicory root showed the highest antioxidant potential for DPPH as well as ABTS with an IC₅₀ (mg mL⁻¹) of 3.76 ± 0.01(methnolic extract) and 1.61 ± 0.31 (Aqueous extract) respectively. The solvent type was seen to strongly affect the antioxidant capacity. No significant difference between the amylase hydrolysis of chicory root powder and standard inulin indicating its ability to remain undigested till it reaches the GI tract. The plant based prebiotics was able to support growth of probiotics however no significant difference (p = 0.48) in Δ log CFU/mL values of probiotic strains among tested prebiotic source were observed. A non dairy synbiotic product was formulated using L. plantarum KCFe6 and chicory with a total carbohydrate content of around 80%. There were no significant differences in the viable cell counts between the probiotic and synbiotic produced stored at (28 °C) and refrigerated conditions (4 °C) the cell count remained above 8 log CFU throughout the study period. The synbiotic product showed higher antimicrobial zones than the probiotic at room temperature and refrigerated conditions for all pathogens except S.typhimurium. The synbiotic product demonstrated higher antioxidant and anti-cholesterol abilities throughout the storage period compared to only probiotics, and storage at 4 °C was found to be better in preservation of functional properties. Overall this study supports the potential of using plant based prebiotics for developing a dry shelf stable synbiotic formulation for enhancing the probiotic viability and its functional properties.

Gamma-aminobutyric acid (GABA) is a bioactive, non-protein forming amino acid renowned for its role as a suppressive neurotransmitter in the mammalian nervous system and its diverse health benefits, including antihypertensive, antidiabetic, antidepressant, and anti-insomnia effects. Rising interest in GABA-enriched health-promoting foods has accelerated efforts towards sustainable and efficient production methods. This study aimed to maximise GABA production in fermented milk using a promising probiotic strain, Lactiplantibacillus plantarum B7, through fermentation conditions optimisation via the one-factor-at-a-time (OFAT) technique. Optimisation with research-grade and food-grade MSG and PLP resulted in GABA yields of 4.715 ± 0.071 g/L (265.89% increase) and 4.846 ± 0.078 g/L (275.97% increase), respectively. Food-grade medium was selected for subsequent development due to safety and cost considerations. Furthermore, L. plantarum B7 cells were immobilised on natural supports (watermelon rind and apple) to enhance cell protection during cold storage of GABA-enriched fermented milk. Both immobilised systems WRBFM (watermelon rind-based) and ABFM (apple-based) demonstrated superior GABA content, lactic acid production, antioxidant activity, and viable cell retention over a 28-day cold storage period compared to free-cell fermented milk (FCFM). These formulations also showed enhanced physicochemical properties, including greater viscosity and better moisture retention, and received higher preference scores in sensory evaluations. Overall, the study highlights the potential of combining fermentation optimisation and natural matrix-based immobilisation to produce stable, high-quality GABA-enriched fermented milk with promising functional and sensory attributes, supporting its application in the development of innovative health-promoting dairy products.

This study developed an enhanced reliability-based integrating (RBI) algorithm by incorporating metaheuristic optimization algorithms into the RBI framework in order to identify optimal gene knockout for strain optimization. To enhance the RBI algorithm, nine metaheuristic optimizations were used: aquila optimization (AO), differential search algorithm (DSA), genetic algorithm (GA), genetic algorithm based on natural selection theory (GABONST), grey wolf optimizer (GWO), komodo mlipir algorithm (KMA), particle swarm optimization (PSO), simulated annealing (SA), and whale optimization algorithm (WOA). The algorithms were simulated with six microbial strain models to optimize the production of succinate and ethanol under aerobic and anaerobic conditions. The analysis indicated that the enhanced algorithms have effectively identified the optimal gene knockout. Furthermore, the three most effective algorithms identified were WOARBI, GWORBI, and GABONSTRBI, which produced optimal mutant strains with the highest succinate or ethanol production rates. This study’s results demonstrated that the metaheuristic optimization algorithms effectively improved the performance of the RBI algorithm.