The mechanisms of pH regulation on promoting volatile fatty acids production from kitchen waste.

The anaerobic acid production experiments were conducted with the pretreated kitchen waste under pH adjustment. The results showed that pH 8 was considered to be the most suitable condition for acid production, especially for the formation of acetic acid and propionic acid. The average value of total volatile fatty acid at pH 8 was 8814 mg COD/L, 1.5 times of that under blank condition. The average yield of acetic acid and propionic acid was 3302 mg COD/L and 2891 mg COD/L, respectively. The activities of key functional enzymes such as phosphotransacetylase, acetokinase, oxaloacetate transcarboxylase and succinyl-coA transferase were all enhanced. To further explore the regulatory mechanisms within the system, the distribution of microorganisms at different levels in the fermentation system was obtained by microbial sequencing, results indicating that the relative abundances of Clostridiales, Bacteroidales, Chloroflexi, Clostridium, Bacteroidetes and Propionibacteriales, which were great contributors for the hydrolysis and acidification, increased rapidly at pH 8 compared with the blank group. Besides, the proportion of genes encoding key enzymes was generally increased, which further verified the mechanism of hydrolytic acidification and acetic acid production of organic matter under pH regulation.

A concise review of the nutritional profiles, microbial dynamics, and health impacts of fermented mushrooms.

Mushrooms have garnered significant attention for their nutritional composition and potential health benefits, including antioxidant, antihypertensive, and cholesterol-lowering properties. This review explores the nutritional composition of edible mushrooms, including their high protein content, essential amino acids, low fat, cholesterol levels, and bioactive compounds with medicinal value. Moreover, the study analyzes the microbiology of mushroom fermentation, focusing on the diverse microbial ecosystem involved in the transformation of raw mushrooms and the preservation methods employed to extend their shelf life. Special emphasis is placed on lactic acid fermentation as a cost-effective and efficient preservation technique. It involves controlling the growth of lactic acid bacteria to enhance the microbial stability and nutritional quality of mushrooms. Furthermore, the bioactivities of fermented mushrooms are elucidated, which are antioxidant, antimicrobial, anticancer, anti-glycemic, immune modulatory, and other biological activities. The mechanisms underlying these bioactivities are explored, emphasizing the role of fermented mushrooms in suppressing free radicals, enhancing antioxidant defenses, and modulating immune responses. Overall, this review provides comprehensive insights into the nutritional composition, microbiology, bioactivities, and underlying mechanisms of fermented mushrooms, highlighting their potential as functional foods with significant health-promoting properties.

Utilization of ripe coconut water in the development of probiotic gelatin.

Background: Desserts with vegetable ingredients are a constantly expanding global market due to the search for alternatives to cow's milk. Fermentation of these matrices by lactic acid bacteria can add greater functionality to the product, improving its nutritional, sensory, and food safety characteristics, as well as creating bioactive components with beneficial effects on health. Concern for health and well-being has aroused interest in byproducts of the industry that have functional properties for the body, such as mature coconut water, a normally discarded residue that is rich in nutrients. This study aimed to develop a probiotic gelatin based on pulp and water from mature coconuts and evaluate the physicochemical characteristics, viability of the Lacticaseibacillus rhamnosus LR32 strain in the medium, as well as the texture properties of the product. Methods: After collection and cleaning, the physicochemical characterization, mineral analysis, analysis of the total phenolic content and antioxidant activity of mature coconut water were carried out, as well as the centesimal composition of its pulp. Afterwards, the gelling was developed with the addition of modified corn starch, gelatin, sucrose, and probiotic culture, being subjected to acidity analysis, texture profile and cell count, on the first day and every 7 days during 21 days of storage, under refrigeration at 5 °C. An analysis of the centesimal composition was also carried out. Results: The main minerals in coconut water were potassium (1,932.57 mg L-1), sodium (19.57 mg L-1), magnesium (85.13 mg L-1) calcium (279.93 mg L-1) and phosphorus (11.17 mg L- 1), while the pulp had potassium (35.96 g kg-1), sodium (0.97 g kg-1), magnesium (2.18 g kg-1), 37 calcium (1.64 g kg-1), and phosphorus (3.32 g kg-1). The phenolic content of the water and pulp was 5.72 and 9.77 mg gallic acid equivalent (GAE) 100 g-1, respectively, and the antioxidant capacity was 1.67 and 0.98 39 g of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) mg-1, respectively. The coconut pulp had 2.81 g 100 g-1of protein, 1.11 g 100 g-1 of 40 ash, 53% moisture, and 5.81 g 100 g-1 of carbohydrates. The gelatin produced during the storage period presented firmness parameters ranging from 145.82 to 206.81 grams-force (gf), adhesiveness from 692.85 to 1,028.63 gf sec, cohesiveness from 0.604 to 0.473, elasticity from 0.901 to 0.881, gumminess from 86.27 to 97.87 gf, and chewiness from 77.72 to 91.98 gf. Regarding the viability of the probiotic microorganism, the dessert had 7.49 log CFU g-1 that remained viable during the 21-day storage, reaching 8.51 CFU g-1. Acidity ranged from 0.15 to 0.64 g of lactic acid 100 g-1. The centesimal composition of the product showed 4.88 g 100 g-1 of protein, 0.54 g 100 g-1 of ash, 85.21% moisture, and 5.37g 100 g-1 of carbohydrates. The development of the gelatin made it possible to obtain a differentiated product, contributing to diversification in the food sector, providing a viable alternative for maintaining consumer health and reducing costs compared to desserts already available on the market.

A review on microbes mediated resource recovery and bioplastic (polyhydroxyalkanoates) production from wastewater.

BACKGROUND: Plastic is widely utilized in packaging, frameworks, and as coverings material. Its overconsumption and slow degradation, pose threats to ecosystems due to its toxic effects. While polyhydroxyalkanoates (PHA) offer a sustainable alternative to petroleum-based plastics, their production costs present significant obstacles to global adoption. On the other side, a multitude of household and industrial activities generate substantial volumes of wastewater containing both organic and inorganic contaminants. This not only poses a threat to ecosystems but also presents opportunities to get benefits from the circular economy. Production of bioplastics may be improved by using the nutrients and minerals in wastewater as a feedstock for microbial fermentation. Strategies like feast-famine culture, mixed-consortia culture, and integrated processes have been developed for PHA production from highly polluted wastewater with high organic loads. Various process parameters like organic loading rate, organic content (volatile fatty acids), dissolved oxygen, operating pH, and temperature also have critical roles in PHA accumulation in microbial biomass. Research advances are also going on in downstream and recovery of PHA utilizing a combination of physical and chemical (halogenated solvents, surfactants, green solvents) methods. This review highlights recent developments in upcycling wastewater resources into PHA, encompassing various production strategies, downstream processing methodologies, and techno-economic analyses. SHORT CONCLUSION: Organic carbon and nitrogen present in wastewater offer a promising, cost-effective source for producing bioplastic. Previous attempts have focused on enhancing productivity through optimizing culture systems and growth conditions. However, despite technological progress, significant challenges persist, such as low productivity, intricate downstream processing, scalability issues, and the properties of resulting PHA.

Sargassum horneri extract fermented by Lactiplantibacillus pentosus SH803 mediates adipocyte metabolism in 3T3-L1 preadipocytes by regulating oxidative damage and inflammation.

Sargassum horneri (S. horneri), a brown seaweed excessively proliferating along Asian coastlines, are damaging marine ecosystems. Thus, this study aimed to enhance nutritional value of S. horneri through lactic acid bacteria fermentation to increase S. horneri utilization as a functional food supplement, and consequently resolve coastal S. horneri accumulation. S. horneri supplemented fermentation was most effective with Lactiplantibacillus pentosus SH803, thus this product (F-SHWE) was used for further in vitro studies. F-SHWE normalized expressions of oxidative stress related genes NF-κB, p53, BAX, cytochrome C, caspase 9, and caspase 3, while non-fermented S. horneri (SHWE) did not, in a H2O2-induced HT-29 cell model. Moreover, in an LPS-induced HT-29 cell model, F-SHWE repaired expressions of inflammation marker genes ZO1, IL1ß, IFNγ more effectively than SHWE. For further functional assessment, F-SHWE was also treated in 3T3-L1 adipocytes. As a result, F-SHWE decreased lipid accumulation, along with gene expression of adipogenesis markers PPARγ, C/EBPα, C/EBPß, aP2, and Lpl; lipogenesis markers Lep, Akt, SREBP1, Acc, Fas; inflammation markers IFN-γ and NF-κB. Notably, gene expression of C/EBPß, IFN-γ and NF-κB were suppressed only by F-SHWE, suggesting the enhancing effect of fermentation on obesity-related properties. Compositional analysis attributed the protective effects of F-SHWE to acetate, an organic acid significantly higher in F-SHWE than SHWE. Therefore, F-SHWE is a novel potential anti-obesity agent, providing a strategy to reduce excess S. horneri populations along marine ecosystems.

Optimization, gene cloning, expression, and molecular docking insights for enhanced cellulase enzyme production by Bacillus amyloliquefaciens strain elh1.

BACKGROUND: In this study, we isolated a cellulase-producing bacterium, Bacillus amyloliquefaciens strain elh, from rice peel. We employed two optimization methods to enhance the yield of cellulase. Firstly, we utilized a one-variable-at-a-time (OVAT) approach to evaluate the impact of individual physical and chemical parameters. Subsequently, we employed response surface methodology (RSM) to investigate the interactions among these factors. We heterologously expressed the cellulase encoding gene using a cloning vectorin E. coli DH5α. Moreover, we conducted in silico molecular docking analysis to analyze the interaction between cellulase and carboxymethyl cellulose as a substrate. RESULTS: The bacterial isolate eh1 exhibited an initial cellulase activity of 0.141 ± 0.077 U/ml when cultured in a specific medium, namely Basic Liquid Media (BLM), with rice peel as a substrate. This strain was identified as Bacillus amyloliquefaciens strain elh1 through 16S rRNA sequencing, assigned the accession number OR920278 in GenBank. The optimal incubation time was found to be 72 h of fermentation. Urea was identified as the most suitable nitrogen source, and dextrose as the optimal sugar, resulting in a production increase to 5.04 ± 0.120 U/ml. The peak activity of cellulase reached 14.04 ± 0.42 U/ml utilizing statistical optimization using Response Surface Methodology (RSM). This process comprised an initial screening utilizing the Plackett-Burman design and further refinement employing the BOX -Behnken Design. The gene responsible for cellulase production, egl, was effectively cloned and expressed in E. coli DH5α. The transformed cells exhibited a cellulase activity of 22.3 ± 0.24 U/ml. The egl gene sequence was deposited in GenBank with the accession number PP194445. In silico molecular docking revealed that the two hydroxyl groups of carboxymethyl cellulose bind to the residues of Glu169 inside the binding pocket of the CMCase. This interaction forms two hydrogen bonds, with an affinity score of -5.71. CONCLUSIONS: Optimization of cultural conditions significantly enhances the yield of cellulase enzyme when compared to unoptimized culturing conditions. Additionally, heterologous expression of egl gene showed that the recombinant form of the cellulase is active and that a valid expression system can contribute to a better yield of the enzyme.

Enhancing Cordycepin in Functional Porridge through Rice Varietal Fermentation with Cordyceps militaris (Ascomycetes) and Utilizing Non-Targeted Metabolomics for Process Enhancement.

Cordyceps militaris, a medicinal fungus rich in cordycepin, shows promise in treating diseases such as cancer, respiratory issues, and COVID-19. This study examines the impact of different Taiwanese rice varieties on its solid-state fermentation, focusing on optimizing cordycepin production. The results indicated that the cordycepin yield was indeed affected by the type of rice used. In terms of the fruiting bodies, germ rice resulted in the highest yield (13.1 ± 0.36 mg/g), followed by brown rice (11.9 ± 0.26 mg/g). In the rice culture medium (RCM), brown rice led to the highest yield (4.77 ± 0.06 mg/g). Using gas chromatography-mass spectrometry and untargeted metabolomics, the study identifies four key volatile components linked to cordycepin, providing insights into developing functional rice porridge products. These findings are significant for advancing cordycepin mass production and offering dietary options for older individuals.

Chemical Constitutes from Mycelia of Laetiporus versisporus (Agaricomycetes).

Edible mushrooms, both wild and cultivated, can be seen as healthy functional food. More and more valuable compounds are obtained from mycelia of macromycetes. However, there was limited report about the medicinal fungus Laetiporus versisporus (Lloyd) Imazeki. Herein, L. versisporus was fermented on rice media and the secondary metabolites of mycelia were investigated. In this study, two-step method was used to obtain fermented products, silica gel column chromatography, recrystallization, medium pressure column chromatography, preparative thin-layer chromatography were applied to separate the chemical constituents. Nine chemical compounds (1-9) including one new triterpenoid acid versisponic acid F were identified by NMR (nuclear magnetic resonance) spectroscopy and MS (mass spectrometry). Seven compounds including monolinoleoyl glycerol, linoleic acid, ergosta-5, 7, 22-triene-3ß-ol, ß-sitosterol, daucosterol, versisponic acid F were isolated for the first time from L. versisporus.

Endophytic Aspergillus fumigatiaffinis: Novel paclitaxel production and optimization insights.

This study investigated the potential of endophytic fungi to produce paclitaxel (Taxol®), a potent anticancer compound widely employed in chemotherapy. This research aimed to identify, confirm, and characterize endophytic fungi capable of paclitaxel (PTX) production and assess their paclitaxel yield. Additionally, it aimed to investigate factors influencing paclitaxel production. A total of 100 endophytic fungal isolates were collected and identified from the roots of Artemisia judaica. Aspergillus fumigatiaffinis exhibited the highest PTX production (26.373 µg L-1) among the isolated endophytic fungi. The strain was identified as A. fumigatiaffinis (Accession No. PP235788.1). Molecular identification confirmed its novelty, representing the first report of PTX production by A. fumigatiaffinis, an endophyte of Artemisia judaica. Optimization through full factorial design of experiments (DOE) and response surface methodology (RSM) significantly enhanced PTX production to 110.23 µg L-1 from 1 g of dry weight of the fungal culture under optimal conditions of pH 8.0, 150 µg L-1 becozyme supplementation, and 18 days of fermentation in potato dextrose broth. The presence of paclitaxel was confirmed using thin layer chromatography, high performance liquid chromatography, and gas chromatography-mass spectrometry. These findings maximize the role of endophytic fungus to produce a secondary metabolite that might be able to replace the chemically produced PTX and gives an opportunity to provide a sustainable source of PTX eco-friendly at high concentrations. KEY POINTS: • Endophytic fungi, like A. fumigatiaffinis, show promise for eco-friendly paclitaxel production • Optimization strategies boost paclitaxel yield significantly, reaching 110.23 µg L -1 • Molecular identification confirms novelty, offering a sustainable PTX source.

Turmeric rhizomes reduced in vitro methane production and improved gas production and nutrient degradability.

The present study aimed to evaluate the effect of dry turmeric rhizomes on in vitro biogas production and diet fermentability. Turmeric rhizomes were included at gradually increased levels: 0, 0.5, 1, 1.5 and 2% of a diet containing per kg dr matter (DM): 500 g concentrate feed mixture, 400 g berseem hay and 100 g rice straw, and incubated for 48 h. Gas chromatography-mass spectrometry analysis showed that ar-turmerone, α-turmerone and ß-turmerone were the major bioactive compounds in the rhizomes. Turmeric rhizomes increased (p < 0.01) asymptotic gas production (GP) and rate and lag of CH4 production and decreased (p < 0.01) rate of GP, lag of GP, asymptotic CH4 production and proportion of CH4 production. Turmeric rhizome administration linearly increased (p < 0.01) DM and fiber degradability and concentrations of total short-chain fatty acids, acetic and propionic acids and ammonia-N and quadratically (p < 0.05) decreased fermentation pH. It is concluded that including up to 2% turmeric rhizomes improved in vitro ruminal fermentation and decreased CH4 production.

A novel simultaneous short-course nitrification, denitrification and fermentation process: bio-enhanced phenol degradation and denitrification in a single reactor.

The feasibility of a simultaneous nitrification, denitrification and fermentation process (SNDF) under electric stirrer agitation conditions was verified in a single reactor. Enhanced activated sludge for phenol degradation and denitrification in pharmaceutical phenol-containing wastewater under low dissolved oxygen conditions, additional inoculation with Comamonas sp. BGH and optimisation of co-metabolites were investigated. At a hydraulic residence time (HRT) of 28 h, 15 mg/L of substrate as strain BGH co-metabolised substrate degraded 650 ± 50 mg/L phenol almost completely and was accompanied by an incremental increase in the quantity of strain BGH. Strain BGH showed enhanced phenol degradation. Under trisodium citrate co-metabolism, strain BGH combined with activated sludge treated phenol wastewater and degraded NO2--N from 50 ± 5 to 0 mg/L in only 7 h. The removal efficiency of this group for phenol, chemical oxygen demand (COD) and TN was 99.67%, 90.25% and 98.71%, respectively, at an HRT of 32 h. The bioaugmentation effect not only promotes the degradation of pollutants, but also increases the abundance of dominant bacteria in activated sludge. Illumina MiSeq sequencing research showed that strain BGH promoted the growth of dominant genera (Acidaminobacter, Raineyella, Pseudarcobacter) and increased their relative abundance in the activated sludge system. These genera are resistant to toxicity and organic matter degradation. This paper provides some reference for the activated sludge to degrade high phenol pharmaceutical wastewater under the action of biological enhancement.

Comparative genomic analysis and optimization of astaxanthin production of Rhodotorula paludigena TL35-5 and Rhodotorula sampaioana PL61-2.

Astaxanthin is a powerful antioxidant known to enhance skin, cardiovascular, eye, and brain health. In this study, the genome insights and astaxanthin production of two newly isolated astaxanthin-producing yeasts (TL35-5 and PL61-2) were evaluated and compared. Based on their phenotypic and genotypic characteristics, TL35-5 and PL61-2 were identified as basidiomycetous yeasts belonging to Rhodotorula paludigena and Rhodotorula sampaioana, respectively. To optimize astaxanthin production, the effects of cultural medium composition and cultivation conditions were examined. The optimal conditions for astaxanthin production in R. paludigena TL35-5 involved cultivation in AP medium containing 10 g/L glucose as the sole carbon source, supplemented with 1.92 g/L potassium nitrate, pH 6.5, and incubation at 20°C for 3 days with shaking at 200 rpm. For R. sampaioana PL61-2, the optimal medium composition for astaxanthin production consisted of AP medium with 40 g/L glucose, supplemented with 0.67 g/L urea, pH 7.5, and the fermentation was carried out at 20°C for 3 days with agitating at 200 rpm. Under their optimal conditions, R. paludigena TL35-5 and R. sampaioana PL61-2 gave the highest astaxanthin yields of 3.689 ± 0.031 and 4.680 ± 0.019 mg/L, respectively. The genome of TL35-5 was 20,982,417 bp in length, with a GC content of 64.20%. A total of 6,789 protein-encoding genes were predicted. Similarly, the genome of PL61-2 was 21,374,169 bp long, with a GC content of 64.88%. It contained 6,802 predicted protein-encoding genes. Furthermore, all essential genes involved in astaxanthin biosynthesis, including CrtE, CrtYB, CrtI, CrtS, and CrtR, were identified in both R. paludigena TL35-5 and R. sampaioana PL61-2, providing evidence for their ability to produce astaxanthin.

Transcriptome Analysis Reveals the Role of Sucrose in the Production of Latilactobacillus sakei L3 Exopolysaccharide.

Latilactobacillus (L.) sakei is a species of lactic acid bacteria (LAB) mostly studied according to its application in food fermentation. Previously, L. sakei L3 was isolated by our laboratory and possessed the capability of high exopolysaccharide (EPS) yield during sucrose-added fermentation. However, the understanding of sucrose promoting EPS production is still limited. Here, we analyzed the growth characteristics of L. sakei L3 and alterations of its transcriptional profiles during sucrose-added fermentation. The results showed that L. sakei L3 could survive between pH 4.0 and pH 9.0, tolerant to NaCl (<10%, w/v) and urea (<6%, w/v). Meanwhile, transcriptomic analysis showed that a total of 426 differentially expressed genes and eight non-coding RNAs were identified. Genes associated with sucrose metabolism were significantly induced, so L. sakei L3 increased the utilization of sucrose to produce EPS, while genes related to uridine monophosphate (UMP), fatty acids and folate synthetic pathways were significantly inhibited, indicating that L. sakei L3 decreased self-growth, substance and energy metabolism to satisfy EPS production. Overall, transcriptome analysis provided valuable insights into the mechanisms by which L. sakei L3 utilizes sucrose for EPS biosynthesis. The study provided a theoretical foundation for the further application of functional EPS in the food industry.

Vinasse treated with charcoal as a molasses diluent for ethanol fermentation.

The demand for new products derived from agro-industrial residues has increased recently. Furthermore, vinasse, a wastewater from ethanol production, needs treatment to be reused in the sugarcane industry, reducing industrial water consumption. This study performed vinasse filtration with charcoal from industrial sugarcane residues and used filtered molasses dilution in ethanolic fermentation. There were five treatments in randomized blocks with three repetitions. The treatments included deionized water and natural vinasse as positive and negative controls, respectively, and filtered vinasse from charcoal made from bamboo, sugarcane bagasse, and straw. Hence, fermentation for ethanol production was performed. Compared with natural vinasse, filtered vinasse with all types of charcoal showed lower soluble solids, total residual reducing sugars, higher ethanol concentrations, and greater fermentative efficiency. Filtered vinasse from bagasse and straw charcoals had efficiencies of 81.14% and 77.98%, respectively, in terms of ethanol production, which are close to those of deionized water (81.49%). In a hypothetical industry, vinasse charcoal filtration and charcoal regeneration should prevent 84.12% of water consumption from environmental resources. This process is feasible because it uses a product of sugarcane residue to treat wastewater and reduce industrial water consumption and vinasse disposal.

Stability and expression of K-ras mimotopes in freeze-dried recombinant Lactococcus lactis NZ3900-fermented milk powder during storage in vacuum packaging.

AIMS: This study aims to evaluate the storage stability of the freeze-dried recombinant Lactococcus lactis NZ3900-fermented milk powder expressing K-ras (Kristen rat sarcoma viral oncogene homolog) mimotopes targeting colorectal cancer in vacuum packaging. METHODS AND RESULTS: The freeze-dried L. lactis-fermented milk powder stored in 4-ply retortable polypropylene (RCPP)-polyamide (PA)-aluminium (AL)-polyethylene terephthalate (PET) and aluminium polyethylene (ALPE) was evaluated throughout 49 days of accelerated storage (38°C and 90% relative humidity). The fermented milk powder stored in 4-ply packaging remained above 6 log10 CFU g-1 viability, displayed lower moisture content (6.1%), higher flowability (43° angle of repose), water solubility (62%), and survivability of L. lactis after simulated gastric and intestinal digestion (>82%) than ALPE packaging after 42 days of accelerated storage. K-ras mimotope expression was detected intracellularly and extracellularly in the freeze-dried L. lactis-fermented milk powder upon storage. CONCLUSIONS: This suggests that fermented milk powder is a suitable food carrier for this live oral vaccine.

Effects of different carbon and nitrogen sources on liamocin production kinetics of Aureobasidium pullulans NBRC 100716 strain.

Liamocins are molecules with a polyol lipid structure produced by rare strains of Aureobasidium pullulans. In recent years, liamocins have attracted attention due to their antibacterial, anticancer and surface-active properties, and promising potential applications have been identified in the food, agriculture, medical and pharmaceutical industries. This study is the first to investigate the effects of different carbon and nitrogen sources on the growth and liamocin production kinetics of A. pullulans NBRC 100716 strain. This strain was selected among six different A. pullulans strains whose liamocin productions were tested by us for the first time. In fermentations carried out in shaking water baths, the carbon source that most supported the liamocin production of this strain was fructose, and the nitrogen source was peptone-yeast extract combination. In the medium containing fructose and the peptone-yeast extract mixture, A. pullulans NBRC 100716 produced 4.26 g liamocin L-1. The specific liamocin production rate (qp) of the strain in this medium was 0.0090 g liamocin/g mo.h. This study is also the first to produce liamocin with a fructophilic A. pullulans strain. Present findings in this research also demonstrated the excellent biosurfactant capacity of the liamocin produced by this strain. The obtained liamocin reduced the water surface tension to a degree that can compete with synthetic surfactants. Furthermore, this is the first report to reveal that the fatty acid profile of liamocin obtained from A. pullulans NBRC 100716 contains an appreciable amount of unsaturated fatty acids and is similar to the composition of vegetable oil.

Efficient production of 22(R)-hydroxycholesterol via combination optimization of Saccharomyces cerevisiae.

22(R)-hydroxycholesterol (22(R)-HCHO) is a crucial precursor of steroids biosynthesis with various biological functions. However, the production of 22(R)-HCHO is expensive and unsustainable due to chemical synthesis and extraction from plants or animals. This study aimed to construct a microbial cell factory to efficiently produce 22(R)-HCHO through systems metabolic engineering. First, we tested 7-dehydrocholesterol reductase (Dhcr7s) and cholesterol C22-hydroxylases from different sources in Saccharomyces cerevisiae, and the titer of 22(R)-HCHO reached 128.30 mg L-1 in the engineered strain expressing Dhcr7 from Columba livia (ClDhcr7) and cholesterol 22-hydroxylase from Veratrum californicum (VcCyp90b27). Subsequently, the 22(R)-HCHO titer was significantly increased to 427.78 mg L-1 by optimizing the critical genes involved in 22(R)-HCHO biosynthesis. Furthermore, hybrid diploids were constructed to balance cell growth and 22(R)-HCHO production and to improve stress tolerance. Finally, the engineered strain produced 2.03 g L-1 of 22(R)-HCHO in a 5-L fermenter, representing the highest 22(R)-HCHO titer reported to date in engineered microbial cell factories. The results of this study provide a foundation for further applications of 22(R)-HCHO in various industrially valuable steroids.

Synthetic biology for Monascus: From strain breeding to industrial production.

Traditional Chinese food therapies often motivate the development of modern medicines, and learning from them will bring bright prospects. Monascus, a conventional Chinese fungus with centuries of use in the food industry, produces various metabolites, including natural pigments, lipid-lowering substances, and other bioactive ingredients. Recent Monascus studies focused on the metabolite biosynthesis mechanisms, strain modifications, and fermentation process optimizations, significantly advancing Monascus development on a lab scale. However, the advanced manufacture for Monascus is lacking, restricting its scale production. Here, the synthetic biology techniques and their challenges for engineering filamentous fungi were summarized, especially for Monascus. With further in-depth discussions of automatic solid-state fermentation manufacturing and prospects for combining synthetic biology and process intensification, the industrial scale production of Monascus will succeed with the help of Monascus improvement and intelligent fermentation control, promoting Monascus applications in food, cosmetic, agriculture, medicine, and environmental protection industries.

Metabolic versatility of anaerobic sludge towards platform chemical production from waste glycerol.

Waste glycerol is produced in excess by several industries, such as during biodiesel production. In this work, the metabolic versatility of anaerobic sludge was explored towards waste glycerol valorization. By applying different environmental (methanogenic and sulfate-reducing) conditions, three distinct microbial cultures were obtained from the same inoculum (anaerobic granular sludge), with high microbial specialization, within three different phyla (Thermodesulfobacteriota, Euryarchaeota and Pseudomonadota). The cultures are capable of glycerol conversion through different pathways: (i) glycerol conversion to methane by a bacterium closely related to Solidesulfovibrio alcoholivorans (99.8% 16S rRNA gene identity), in syntrophic relationship with Methanofollis liminatans (98.8% identity), (ii) fermentation to propionate by Propionivibrio pelophilus strain asp66 (98.6% identity), with a propionate yield of 0.88 mmol mmol-1 (0.71 mg mg-1) and a propionate purity of 80-97% and (iii) acetate production coupled to sulfate reduction by Desulfolutivibrio sulfoxidireducens (98.3% identity). In conclusion, starting from the same inoculum, we could drive the metabolic and functional potential of the microbiota towards the formation of several valuable products that can be used in industrial applications or as energy carriers. KEY POINTS: Versatility of anaerobic cultures was explored for waste glycerol valorization Different environmental conditions lead to metabolic specialization Biocommodities such as propionate, acetate and methane were produced.

Improvement of Bacillus subtilis PI agarase production, hydrolysate scavenging capability assessment, and saccharification of algal biomass for green ethanol generation.

The goal of the current work was to optimize the growth parameters needed to manufacture agarase enzyme from a non-marine PI strain of Bacillus subtilis on an agar-based medium. Using Plackett-Burman design (PBD), nine process parameters were evaluated, and agar, peptone, and yeast-extract were identified as the most significant independent factors influencing agarase production with confidence levels more than 90%. To evaluate the optimal concentrations of the indicated process parameters on agarase production, the Box-Behnken design (BBD) was applied. After optimization, B. subtilis strain PI produced 119.8 U/ml of agarase, representing a 1.36-fold increase. In addition the agar hydrolysate fermented products contain the liberated oligosaccharide acts as strong antioxidant which has 62.4% scavenging activity. Also, the agarase yields increased (1141.12, 1350.253, 1684.854 and 1921.863 U/ml) after substitution the agar with algal biomass of Carolina officinalis at different concentrations (2, 5, 10 and 15%), respectively. After completing the saccharification process, the resulted hydrolysate was used to produce ethanol through fermentation with Pichia pastoris yeast strain as an economical method giving yields (6.68317, 7.09748, 7.75648 and 8.22332 mg/ml), that are higher than using yeast extract peptone dextrose (YPD) medium (4.461 mg/ml).