Food waste (FW) has traditionally been disposed by incineration or landfilling; however, it can be converted to green methane (GM) via anaerobic digestion, and GM can be used as fuel for light-duty natural gas vehicles (LDNGVs). A lifecycle assessment (LCA) of FW-based GM production and LDNGV operation in China, a new scenario, was performed. The LCA results were compared with those for the conventional FW treatment, where a “well-to-wheel” system boundary including FW collection, GM production from FW, and vehicle manufacturing, operation, and disposal was defined. The LCA results showed that the global warming impacts of the new FW scenario are 44.3% lower than those of the conventional option. The fine particulate matter formation impact of the new FW scenario was dominated by the displacement effect of electricity supply to anaerobic digestion, followed by CO₂ adsorption by the primary source. The sensitivity analysis showed that hydroelectric power as the best primary source for electricity supply could substantially reduce both global warming and FRS in the new scenario. In the short term, the proposed FW scenario could be a feasible option for achieving sustainable society by minimizing environmental impacts of FW treatment. Full article

The manufacture of fermented milk products has a long history, and these products were initially produced either from spontaneous fermentation or using a batch of previously produced product, that is, back-slopping. Milk of different mammal species has traditionally been used for the manufacture of fermented milk products. Cow’s milk is the basis for most dairy fermented products around the world. Milk from other mammals, including sheep, goat, camel, mare, buffalo, and yak may have been historically more important and remain so in certain regions. The milks from different species have differences in chemical composition and in certain, vital for the fermentation, components. The diversity of fermented milk products is further influenced by the wide variety of manufacturing practices. A great number of fermented dairy products have been traditionally produced worldwide, and many of them are still produced either following the same traditional process or manufactured industrially, using standardized processes under controlled conditions with specified starter cultures. The evolution from traditional to industrial production, their specific regional differences, their special characteristics, and the microbiological aspects of fermented dairy products are discussed. Throughout the evolution of fermented milk products, functional and therapeutic properties have been attributed to certain components and thus, yogurts and fermented milks have gained a significant market share. These products have gained wide global recognition as they meet consumers’ expectations for health-promoting and functional foods. The exploitation of microbiological methods based on DNA (or RNA) extraction and recently high-throughput techniques allowed for the accurate identification of the microbiota of fermented milk products. These techniques have revealed the significance of the properties of the autochthonous microbes and provided novel insights into the role of the microbiota in the functional and organoleptic properties of many fermented milk products. Full article

The aminoglycoside antibiotic neomycin has broad antibacterial properties and is widely used in medicine and agriculture. With the discovery of neomycin’s potential applications in treating tumors and SARS-CoV-2, it is necessary to accelerate the biosynthesis of neomycin. In the present study, we investigated the effects of various inorganic salts on neomycin B (the main active neomycin) biosynthesis in Streptomyces fradiae SF-2. We found that 60 mM (NH₄)₂SO₄ could promote neomycin B biosynthesis and cell growth most effectively. Further comparative transcriptomic analyses revealed that 60 mM (NH₄)₂SO₄ inhibited the EMP and TCA cycles and enhanced the expression of neo genes involved in the neomycin B biosynthesis pathway. Finally, a neomycin B potency of 17,399 U/mL in shaking flasks was achieved by overexpressing neoE and adding 60 mM (NH₄)₂SO₄, corresponding to a 51.2% increase compared with the control S. fradiae SF-2. In the present study, the mechanism by which (NH₄)₂SO₄ affects neomycin biosynthesis was revealed through transcriptomics, providing a reference for the further metabolic engineering of S. fradiae SF-2 for neomycin B production. Full article

The purpose of this research was to investigate the possible antibacterial, antifungal, antioxidant, and anticancer effects of nickel (Ni²⁺)-doped hydroxyapatite (HAp) nanoparticles (NPs) synthesized using the sol–gel approach. X-ray powder diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Raman spectroscopy (Raman), field-emission scanning electron microscopy (FESEM), and elemental analysis were used to characterize the Ni²⁺-doped HApNPs. X-ray diffraction investigation showed that the nanoscale structure of Ni²⁺-doped HApNPs was hexagonal, with an average crystallite size of 39.91 nm. Ni²⁺-doped HApNPs were found to be almost spherical in form and 40–50 nm in size, as determined by FESEM analysis. According to EDAX, the atomic percentages of Ca, O, P, and Ni were 20.93, 65.21, 13.32, and 0.55, respectively. Ni²⁺-doped HApNPs exhibited substantial antibacterial properties when tested in vitro against several pathogens, including Escherichia coli, Shigella flexneri, Klebsiella pneumoniae, Pseudomonas aeruginosa, and Staphylococcus aureus. Antibacterial activity, at 50 mg tested concentration, demonstrated superior effects on G^-ve bacteria than G^+ve pathogens. The antifungal activity of Oidium caricae, Aspergillus flavus, and A. niger revealed a zone of inhibition of 23, 11, and 5 mm, respectively. These actions rely on the organism’s cell wall structure, size, and shape. Incorporating Ni²⁺ into HApNPs allows them to function as powerful antioxidants. Ni²⁺-doped HApNPs had a good cytotoxic impact against the HeLa cell line, which improved with increasing concentration and was detected at a 68.81 µg/mL dosage. According to the findings of this study, the Ni²⁺-doped HApNPs are extremely promising biologically active candidates owing to their improved functional features. Full article

The probiotic fermentation of lamb liver paste is a new method with which to utilize sheep by-products and address the issue of waste. In this study, a pH meter, chromaticity meter, texture analyzer, and gas chromatograph–mass spectrometer (GC–MS) were used to determine various indicators. The objective was to investigate the effect of fermentation on the physical properties and aroma of lamb liver paste. The results showed that the L* (brightness), a* (redness), and b* (yellowness) of the samples were significantly higher in the starter fermentation group than in the other two groups after storage for 0, 1, 7, 14, 21, and 28 days (p < 0.05). In addition, cohesiveness, adhesion, and chewiness were lower in the starter fermentation group after 7 days (p < 0.05). TVB-N and fat were lower in the starter fermentation group compared to the sterilization group at 28 days. pH was significantly lower in the starter fermentation group at the beginning of storage, and lactic acid bacteria numbers were significantly higher than in the sterilization groups (p < 0.05). Important aroma compounds, such as 2-undecenal, 1-octen-3-ol, and anethole, were significantly higher in the starter fermentation group than in the sterilization group (p < 0.05). Fermented lamb liver paste is a new by-product that exhibits a high degree of freshness and a low degree of fat oxidation during storage. This study provides a theoretical basis for future industrial production. Full article

During the beer brewing process, some compounds are formed in the primary fermentation step and may affect the final quality of beer. These compounds, called off flavors, such as diacetyl, are produced during fermentation and are related to a buttery taste. The use of acetolactate decarboxylase (ALDC) in the traditional beer brewing process may significantly increase productivity since it allows for a faster decrease in the adverse flavor caused by diacetyl. However, production costs directly impact its application. For this reason, we analyzed the effect of different cultivation media on ALDC production by Bacillus subtilis ICA 56 and process economics. Different carbon and nitrogen sources, including agro-industrial residues, were evaluated. The best result was obtained using sugarcane molasses and corn steep solids (CSS), allowing a 74% reduction in ALDC production cost and an enzyme activity of 4.43 ± 0.12 U·mL⁻¹. The enzymatic extract was then characterized, showing an optimum temperature at 40 °C and stability at different pH levels, being able to maintain more than 80% of its catalytic capacity between pH values of 3.6 and 7.0, with higher enzymatic activity at pH 6.0 (50 mM MES Buffer), reaching an ALDC activity of 5.30 ± 0.06 U·mL⁻¹. Full article

Dark fermentation (DF) is a promising process for mitigating environmental pollution and producing “green” H₂. However, wider implementation and scaling of this technology is hampered by insufficient process efficiency. In this work, for the first time, the effect of innovative pretreatment of cheese whey (CW) in a vortex layer apparatus (VLA) on characteristics and DF of CW was studied. Pretreatment in VLA resulted in a heating of the CW, slight increase in pH, volatile fatty acids, iron, and reduction in fat, sugar, and chemical oxygen demand (COD). The biochemical hydrogen potential test and analysis of H₂ production kinetics confirmed the significant potential of using VLA in enhancement of dark fermentative H₂ production. The maximum potential H₂ yield (202.4 mL H₂/g COD or 3.4 mol H₂/mol hexose) was obtained after pretreatment in VLA for 45 s and was 45.8% higher than the control. The maximum H₂ production rate after 5 and 45 s of pretreatment was 256.5 and 237.2 mL H₂/g COD/d, respectively, which is 8.06 and 7.46 times higher than in the control. The lag phase was more than halved as a function of the pretreatment time. The pretreatment time positively correlated with the total final concentration of Fe²⁺ and Fe³⁺ and negatively with the lag phase, indicating a positive effect of pretreatment in VLA on the start of H₂ production. Full article

Probiotics improve gut health; however, their intake through diet is mainly in the form of dairy products, which represents a challenge to lactose-intolerant individuals and vegetarians. This study aimed to determine the prebiotic potential of baobab and to evaluate the potential of using fermented baobab-based beverages as functional foods. The prebiotic content of baobab fruit pulp was determined. Lactic acid bacteria (LAB) were isolated from raw milk samples, identified through phenotypic and molecular methods, and evaluated for their probiotic potential. Three potential non-dairy synbiotic functional beverages using baobab fruit pulp fermented with potential probiotic Limosilactobacillus fermentum and mixed with milk, water, and apple juice separately were produced. The growth and survival of probiotic L. fermentum in the beverages at room (25 °C) and refrigeration (4 °C) temperatures for 3 weeks were determined. Baobab fruit pulp contained phytochemicals, vitamins, fatty acids, inulin, and fructooligosaccharides. Sequence alignment of the LAB isolates identified homologous sequences of Lacticaseibacillus casei, Limosilactobacillus fermentum, Lactiplantibacillus plantarum, Lentilactobacillus buchneri, and Lactiplantibacillus pentosus with 97.2–98.5% similarity. All the lactic acid bacteria did not produce DNAse and gelatinase enzymes, exhibited antagonistic activity against test pathogenic organisms, and demonstrated tolerance to bile salt, simulated gastric juice, and acid. The viability of L. fermentum increased from an initial inoculum size of 10⁶–10⁸ CFU/mL in the baobab-based beverages and remained constant at 10⁸ CFU/mL both at room and refrigeration temperatures. However, after three weeks, the viability of L. fermentum in the synbiotic beverages reduced to 10⁷ CFU/mL. Refrigerated synbiotic beverages had more viable L. fermentum cells (8.04–8log₁₀ CFU/mL) than those stored at room temperatures (7.95–7.7log₁₀ CFU/mL) after three weeks of storage. This study has shown that baobab fruit pulp has prebiotic potential and can be used in the production of a non-dairy functional beverage. Full article

Antibiotics have been used to maintain the overall health of poultry by increasing production efficiency, promoting growth, and improving intestinal function for more than 50 years. However, they have a number of side effects, such as antibiotic resistance, gut dysbiosis, destruction of beneficial bacteria, and the potential to spread diseases to humans. In order to address the aforementioned issues, a lot of effort is put into the development of antibiotic alternatives. One of them is the use of probiotics that can be added to the feed in order to increase poultry performance and avoid the aforementioned problems. Probiotics are live microorganisms consumed as feed additives or supplements. They function in the poultry gastrointestinal tract to benefit the host. Probiotics improve growth performance, bone health, meat and eggshell quality. The addition of probiotics to the diet also positively affects the immune response, intestinal microflora, and disease resistance. Careful selection of probiotic strains is of utmost importance. This review focuses on the significance of probiotics as a potential antibiotic-free alternative and the way in which they can be used as supplements in poultry feed for boosting production and safeguarding health. Full article

To explore the effects of microbial community changes on the key flavor substances in base Baijiu, this study analyzed the microbiome of the pre-pit fermentation grains using high-throughput sequencing technology and determined the flavor substances of the base Baijiu by GC-FID. The results showed the microbial community changed dynamically between the different rounds, as well as bacteria and fungi displayed different succession patterns. Next, the variations of skeletal flavor substances in the base Baijiu were analyzed by multiomics, and it was found that alcohols, acids, and esters were the most abundant, accounting for 88.16–98.87% of the total flavor substances, and decreased with the increase of the rounds. By calculating the Spearman coefficient, it was found that microorganisms such as Acinetobacter, Oceanobacillus, Saccharomyces, and Byssochlamys were significantly correlated with the n-Propano and 2,3-Butanediol and other components in the base Baijiu. Finally, 15 flavor substances such as Acetaldehyde, Propionaldehyde, and Isobutyraldehyde were identified as key substances by OAV analysis. This study is the first to reveal the potential association between the microbial community of pre-pit fermentation grains and flavor of base Baijiu and has the benefit of improving the quality of base Baijiu. Full article

Food waste-based biorefineries are considered an essential concept for the implementation of a sustainable circular economy. In this study, cheese whey powder (CWP), a dairy industry waste, was utilized to produce cyclosporin A (CsA). As it is difficult to valorize CWP because its components vary depending on the origin, a process for sugar conversion via acid hydrolysis was designed to obtain reproducible results using refined whey powder (WP) of a consistent quality. Acid hydrolysis was carried out using 2% (w/w) HCl and biomass loading of 50 g/L at 121 °C for 20 min. CWP hydrolysates were utilized to ferment Tolypocladium inflatum ATCC 34921. CsA production was found to be 51.3 mg/L at 12 days, a 1.4-fold increase compared to the control (commercial glucose, 36.3 mg/L). Our results showed that 100 g CWP can be converted to 81.8 mg of CsA. This finding demonstrated that CWP can be used as a sustainable feedstock for biorefineries. Full article

Economic conversion of biomass to biofuels and chemicals requires efficient and complete utilization of xylose. Saccharomyces cerevisiae strains engineered for xylose utilization are still considerably limited in their overall ability to metabolize xylose. In this study, we identified causative mutations resulting in improved xylose fermentation of an adapted S. cerevisiae strain expressing codon-optimized xylose isomerase and xylulokinase genes from the rumen bacterium Prevotella ruminicola. Genome sequencing identified single-nucleotide polymorphisms in seven open reading frames. Tetrad analysis showed that mutations in both PBS2 and PHO13 genes were required for increased xylose utilization. Single deletion of either PBS2 or PHO13 did not improve xylose utilization in strains expressing the xylose isomerase pathway. Saccharomyces can also be engineered for xylose metabolism using the xylose reductase/xylitol dehydrogenase genes from Scheffersomyces stipitis. In strains expressing the xylose reductase pathway, single deletion of PHO13 did show a significant increase xylose utilization, and further improvement in growth and fermentation was seen when PBS2 was also deleted. These findings will extend the understanding of metabolic limitations for xylose utilization in S. cerevisiae as well as understanding of how they differ among strains engineered with two different xylose utilization pathways. Full article

This study explored the effects of two mixed fermentation methods: one was fermenting a soymilk and milk mixture by a lactic acid bacteria fermenting agent at 0.1 g/kg and 42 °C until the acidity was 70 °T, which was set as the MFSM method, and the other was fermenting milk alone by lactic acid bacteria at 42 °C for 12 h, placing it in a 4 °C refrigerator after acidification for 24 h and then mixing it with soymilk at a 1.5:1 ratio and storing the mixture at 4 °C, which was set as the SMFSM method. The quality and flavor of the soymilk and milk mixture products were investigated on the 0th, 15th and 30th days during storage. The changes in acidity, pH, number of viable bacteria, viscosity, water-holding capacity, texture, rheological properties, sensory quality and volatile flavors were determined. The results showed that compared with the fermented soymilk and milk mixtures under the MFSM method, the samples of fermented soymilk and milk mixtures under the SMFSM method showed a significant slowdown of acidification during storage, so that the sensory quality of the products was almost unaffected by acidity on the 30th day of storage. Furthermore, the number of viable bacteria was greater than 7 log cfu/mL. The water holding capacity did not change significantly until the 30th day. There was also no whey precipitation, indicating good stability. The samples in SMFSM mode had higher aromatic contents and beans during storage than the fermented soymilk and milk mixtures in MFSM mode. The rich variety of volatile flavors and the presence of acetoin, 2-heptanone, and (E,E)-3,5-octadien-2-one throughout the storage period allowed the samples to maintain a good sensory flavor during storage. Full article

The oleaginous fungus Mucor circinelloides has been studied for microbial oil production. Solid–state fermentation may be more suitable for lipid production than submerged fermentation due to its special filamentous structure and lower fermentation costs. M. circinelloides WJ11 under solid–state fermentation indicated that the total fatty acid content of mycelia was significantly higher than that of spores (15.0 and 10.4% in mycelia and spores after 192 h, respectively), while the biomass of the fungal mycelia was lower than that of the spores, reaching 78.2 and 86.9 mg/g, respectively. Transcriptomic studies showed that a total of 9069 genes were differentially expressed between spores and mycelia during solid–state fermentation, of which 4748 were up-regulated and 4321 were down-regulated. Among them, triglyceride-related synthases in M. circinelloides were significantly up-regulated in the mycelia. The mRNA expression level of ATP: citrate lyase was obviously increased to provide more acetyl-CoA for fatty acid synthesis in mycelia, moreover, the metabolism of leucine and isoleucine can also produce more acetyl-CoA for lipid accumulation in M. circinelloides. For NADPH supply, the expression of the pentose phosphate pathway was significantly up-regulated in mycelia, while NADP⁺-dependent malic enzyme was also increased by 9.5-fold under solid–state fermentation. Compared with gene expression in spores, the autophagy pathway was clearly up-regulated in mycelia to prove that autophagy was related to lipid accumulation in M. circinelloides. Full article

Bacillus thuringiensis is the leading microbial-based biopesticide, thanks to its parasporal crystal proteins or δ-endotoxins, which are toxic to insect larvae upon ingestion. Once in the insect larvae midgut, the crystal is solubilized by the alkaline pH and the δ-endotoxins activated by proteolytic cleavage. Thanks to its high efficiency as a biopesticide, several efforts have been made to enhance its growth and δ-endotoxins production, in various types of culture media. In this study, a culture medium based on wheat bran (WB), the by-product of cereal grain milling, was used to grow Bacillus thuringiensis and produce δ-endotoxins. Using the response surface methodology (RSM), the effects of three variables were evaluated: WB particles granulometry, their concentration, and their agitation in a 48-h shake-flask culture at 30 °C. Three response parameters were targeted: δ-endotoxins production, final culture pH, and dry-matter consumption. According to the RSM results, the optimum would be at 3.7 g WB/50 mL, with a granulometry above 680 μm and agitation between 170 and 270 rpm. This study is key to developing natural and cheap culture media that can be used at an industrial level for Bacillus thuringiensis-based biopesticides. Full article