Enzyme-production microorganisms typically occupy a dominant position in composting, where cellulolytic microorganisms actively engage in the breakdown of lignocellulose. Exploring strains with high yields of cellulose-degrading enzymes holds substantial significance for the industrial production of related enzymes and the advancement of clean bioenergy. This study was inclined to screen cellulolytic bacteria, conduct genome analysis, mine cellulase-related genes, and optimize cellulase production. The potential carboxymethylcellulose-hydrolyzing bacterial strain Z2.6 was isolated from the maturation phase of pig manure-based compost with algae residuals as the feedstock and identified as Bacillus velezensis. In the draft genome of strain Z2.6, 31 related cellulolytic genes were annotated by the CAZy database, and further validation by cloning documented the existence of an endo-1,4-β-D-glucanase (EC 3.2.1.4) belonging to the GH5 family and a β-glucosidase (EC 3.2.1.21) belonging to the GH1 family, which are predominant types of cellulases. Through the exploration of ten factors in fermentation medium with Plackett–Burman and Box–Behnken design methodologies, maximum cellulase activity was predicted to reach 2.98 U/mL theoretically. The optimal conditions achieving this response were determined as 1.09% CMC-Na, 2.30% salinity, and 1.23% tryptone. Validation under these specified conditions yielded a cellulose activity of 3.02 U/mL, demonstrating a 3.43-fold degree of optimization. In conclusion, this comprehensive study underscored the significant capabilities of strain Z2.6 in lignocellulolytic saccharification and its potentialities for future in-depth exploration in biomass conversion.

A Gram-stain-negative, facultatively aerobic, pink and oval bacterium, designed OS4^T, was isolated from a sediment sample taken from a coastal zone in China. The growth of OS4^T occurred at 20–37 °C (optimal 25 °C), pH 7.0–8.5 (optimal pH 8.0), in 0–5.0% (w/v) NaCl (optimal 2.0%). According to the phylogenetic analysis, strain OS4^T showed the highest sequence similarity (96.04%) with Jannaschia aquimarina GSW-M26^T and shared 94.98% similarity with the type species of genus Jannaschia-strain J. helgolandensis 14858^T. Chemotaxonomic analysis showed that the sole respiratory quinone was ubiquinone 10, and the major fatty acids (>5.0%) included C_18:1 ω6c/ω7c, C_18:0, and C_10:0 3OH. The polar lipids consist of three phospholipids, two unknown amino-lipids, and four unknown glycerolipids. The DNA G + C content was 72.7 mol%. Based on the evidence presented in this study, strain OS4^T represents a novel species of the genus Jannaschia, for which the name Jannaschia sedimins sp. nov. is proposed. The type strain is OS4^T (=KCTC 82508^T = MCCC 1K03755^T). Both the phenotypic and the genetic analysis on the antimicrobial resistance genes indicate that OS4^T is resistant to a wide range of classes of antibiotics, which highlights that the ocean could potentially serve as the natural reservoir of antimicrobial resistance genes.