Screening new Clostridium strains that can efficiently utilize lignocellulose to produce hydrogen is extremely important for dark fermentative hydrogen production. In this study, a mesophilic hydrogen-producing bacterium, identified as Clostridium populeti FZ10, was newly isolated from compost acclimated by microcrystalline cellulose. The strain could produce hydrogen from various cellulosic substrates. The performances of hydrogen production from microcrystalline cellulose (MCC) and corn stalk (CS) were especially investigated. The maximum hydrogen yield and hydrogen production rate from MCC were 177.5 ± 4.8 mL/g and 7.7 ± 0.2 mL·g⁻¹·h⁻¹, respectively. Furthermore, scanning electron microscopy (SEM) images showed that the structure of CS was destroyed after fermentation, which could be attributed to the presence of exoglucanase, endoglucanase, β-glucosidase and xylanase produced by Clostridium populeti FZ10. The maximum hydrogen yield and hydrogen production rate from CS were 92.5 ± 3.7 mL/g and 5.9 ± 0.2 mL·g⁻¹·h⁻¹,respectively, with a cellulose degradation of 47.2 ± 2.3% and a hemicellulose degradation of 58.1 ± 2.0%. This study demonstrates that Clostridium populeti FZ10 is an ideal candidate for directly converting lignocellulose into biohydrogen under mesophilic conditions. The discovery of strain C. populeti FZ10 has special significance in the field of bioenergy.

This study investigated the feasibility of producing L-lactic acid (LA) from dry corn stalk (DCS) that was pretreated by ensiling by an anaerobic microbial community consisting of Bacillus coagulans, Lactobacillus fermentum, and Enterococcus durans. After 28 days of ensiling, the LA and acetic acid content in the microsilage was 2.04 ± 0.08% and 0.38 ± 0.01%, respectively, and the pH was 4.47 ± 0.13. Enterococcus and Lactobacillus became the dominant microbiota during the ensiling process. Twenty-eight-day-old microsilage was then subjected to fermentation by B. coagulans to produce LA in a simultaneous saccharification and co-fermentation process. The enzymatic hydrolysis yield reached >96%. The maximal concentration of LA reached 18.54 ± 0.52 g/L with a substrate concentration of 5%, where the yield of LA was 0.31 ± 0.01 g/g DCS and the optical purity of the product LA was >97%. Anaerobic ensiling is viable for the pretreatment of biomass for the production of value-added chemicals.

Mixed-culture products of Rhodotorula glutinis and Chlorella vulgaris can enhance the antioxidant capacity of target organisms. However, their intrinsic carotenoids exhibit poor stability and bioaccessibility, which hinders the industrial application of related functional feeds. In this study, yeast-algal cells harvested from a 5 L fermenter were double-coated with gelatin and gum arabic. Process parameters were optimized by single-factor experiments and response surface methodology (RSM). Encapsulation efficacy was characterized by zeta potential analysis, Fourier transform infrared (FT-IR) spectroscopy and scanning electron microscopy (SEM). The results showed that the maximum encapsulation rate reached 65.87% at the optimal conditions: wall material concentration of 1.34%, core-to-wall ratio of 58.80%, gelatin proportion in wall materials of 35.40% and curing agent addition of 0.17%. Characterization revealed that re-crystallization-regulated zeta potential facilitated the formation of dense wall structures. Storage stability tests demonstrated enhanced antioxidant retention, and in vitro digestion assays verified favorable sustained-release properties. This study effectively improves carotenoid stability and bioaccessibility, providing technical support for high-performance feed additives.