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.

Members of the genus Marinomonas are known for their environmental adaptation and metabolically versatility, with abundant proteins associated with antifreeze, osmotic pressure resistance, carbohydrase and multiple secondary metabolites. Comparative genomic analysis focusing on secondary metabolites and orthologue proteins were conducted with 30 reference genome sequences in genus Marinomonas. In this study, a Gram-stain-negative, rod-shaped, non-flagellated and strictly aerobic bacterium, designated as strain E8^T, was isolated from the red algae (Gelidium amansii) in the coastal of Weihai, China. Optimal growth of the strain E8^T was observed at temperatures 25–30 ℃, pH 6.5-8.0 and 1–3% (w/v) NaCl. The DNA G + C content was 42.8 mol%. The predominant quinone was Q-8 and the major fatty acids were C_16:0, summed feature 3 and summed feature 8. The main polar lipids were phosphatidylglycerol (PG) and phosphatidylethanolamine (PE). Based on data obtained from this polyphasic taxonomic study, strain E8^T belongs to a novel species of the genus Marinomonas, for which the name Marinomonas algarum is proposed. The type strain is E8^T (= KCTC 92201^T = MCCC 1K07070^T).

A Gram-stain-negative, strictly aerobic, non-flagellated, oxidase- and catalase-positive, rod-shaped marine bacterium, designated strain DM8^T, was isolated from the intestine of Trichiurus japonicus in Weihai, China. The strain optimally grew at 25-35℃, with 1.0-4.0% (w/v) NaCl and at pH 7.0-8.0. Its colonies were circular, slightly yellow, non-transparent, smooth, and approximately 0.8-1.5 mm in diameter, after being cultured for 48h on marine agar 2216. Based on the result of phylogenetic analysis of 16S rRNA gene sequence, strain DM8^T had close relationship with Oceanisphaera profunda SM1222^T (96.9%) and the similarity between DM8^T and the type strain Oceanisphaera litoralis DSM 15406^T was 94.7%. Genome sequencing revealed a genome size of 3,109,059 bp and a G+C content of 46.9 mol%. It had Q-8 as the sole respiratory quinone and possessed C_16:0, summed features 3 (C_16:1ω7c/C_16:1ω6c) and summed features 8 (C_18:1ω7c/C_18:1ω6c) as major fatty acids. The major polar lipid profile was composed of phosphatidylglycerol and phosphatidylethanolamine. Based on the phenotypic, chemotaxonomic characterisations, phylogenetic properties and genome analysis, strain DM8^T should represent a novel species of the genus Oceanisphaera, for which the name Oceanisphaera pacifica sp. nov. is proposed. The type strain is DM8^T (=KCTC 82764^T =MCCC 1K06133^T).

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.