Cellulomonas taurus sp. nov., a novel bacteria with multiple hydrolase activity isolated from livestock, and potential application in wastewater treatment

A Gram-positive, smooth, sub-transparent, faint yellow,0.5-0.7 µm diameter, rod shaped aerobic or facultative aerobic strain P40-2^Twas isolated from livestock farms in Northeast China. Strain P40-2^T grew at 25-40 °C (optimum 30-38 °C), and in 0-4% (w/v) NaCl (optimum 0%) in LB medium. Based on 16S rRNA gene sequence analysis, strain P40-2^T belongs to the class Cellulomonas and is most closely related to C. denverensis strain W6929, C. pakistanensis strain NCCP-11and C. hominis strain CE40.DNA-DNA hybridization rate of strain P40-2^T was 29%, and the ANI with C.denverensisstrainW6929 was 85.33%. The genome is 3437431 bp long with a G + C content of 71.99%. Of the 3177 predicted genes, 3119 were protein-coding genes and 58 were RNA encoding genes. The chemotaxonomic data: menaquinone was MK-9(H₄), anteiso-C_15: 0, C_16:0 and anteiso-C_17: 0 were the major cellular fatty acids, and the main cell-wall amino acids were ornithine,alanine, glycine and glutamate. The cell wall peptidogly can sugars included glucose, rhamnose, galactose and mannose. The polar lipid present were DPG, PG, PE, and PIM. On the basis of DNA-DNA relatedness, phylogenetic position, complete genome sequence and physiological characteristics, strain P40-2^T can be differentiated from other species of the genus Cellulomonas with validly published names and thus represents a novel species, for which the name Cellulomonas taurus is proposed. The type strain is Cellulomonas taurus P40-2^T (= CGMCC No.1.17732^T).The acute toxicity test in mice showed that LD₅₀ of strain P40-2^T was rather high with 1.5 × 10¹¹ CFU/mouse, which indicated low pathogenicity. Drug susceptibility showed that strainP40-2^T was resistant to most antibiotics and only sensitive to six antibiotics. Strain P40-2^T contained a variety of hydrolytic enzymes including the ability to hydrolyze cellulose, β-glucan, chitin, xylan, and casein. Microbial flocculant MBF-P40 for sewage was prepared with strain P40-2^T, after strain P40-2^T was confirmed that had good flocculation effect. MBF-P40 was used to prepare flocculation rate of 99.40%. MBF-P40 treatmented sewage from eight different sources. Flocculation rate for pig farm wastewater was 96.07%, COD removal rate is 71.05%, ammonia nitrogen removal rate is 18.22%. The result shows that MBF-P40 has a good flocculation effect, and good prospect of development and application for wastewater treatment.