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Straw cellulose is an abundant renewable resource in nature. In recent years, the conversion of cellulose from waste straw into biofuel by specific microorganisms' fragmentation has attracted extensive attention. Although many bacteria with the ability to degrade cellulose have been identified, comprehensive bioinformatics analyses of these bacteria remain limited, and research exploring optimal fragmentation conditions is scarce. Our study involved the isolation and screening of bacteria from various locations in Yangzhou using carboxymethyl cellulose (CMC) media. Then, the cellulose-degrading bacteria were identified using 16S rRNA and seven candidate bacterial strains with cellulose degrading ability were identified in Yangzhou city for the first time. The cellulase activity was determined by the 3,5-dinitrosalicylic acid (DNS) method in different fragmentation conditions, and finally two bacteria strains with the strongest cellulose degradation ability were selected for whole genome sequencing analysis. Sequencing results revealed that the genome sizes of Rhodococcus wratislaviensis YZ02 and Pseudomonas Xanthosomatis YZ03 were 8.51 Mb and 6.66 Mb, containing 8,466 and 5,745 genes, respectively. A large number of cellulose degradation-related genes were identified and annotated using KEGG, GO and COG analyses. In addition, genomic CAZyme analysis indicated that both R. wratislaviensis YZ02 and P. Xanthosomatis YZ03 harbor a series of glycoside hydrolase family (GH) genes and other genes related to cellulose degradation. Our finding provides new options for the development of cellulose-degrading bacteria and a theoretical basis for improving the cellulose utilization of straw. [ABSTRACT FROM AUTHOR]

In order to obtain the new cellulose-degrading bacteria at normal temperature, a bacterial strain named as 18B with cellulosedegrading ability was isolated and purified from garden compost in this study. Congo red staining experiment and filter paper degradation experiment were conducted to verify its cellulose-degradation ability. 16S rRNA sequence alignment and whole genome alignment confirmed that it belonged to the genus Olivibacter, and was the closest to Olivibacter jilunii 14-2AT . Further comparative physiological and biochemical characterization revealed differences with O. jilunii 14-2AT in terms of growth temperature, oxidase and glycolysis. The strain 18B grew in the range of 12-48℃, and the optimal growth temperature was 30-37℃ . O. jilunii 14-2AT grew at 4-42℃ . Strain 18B was positive for oxidase and negative for glycolysis, while O. jilunii 14-2AT had no oxidase activity and was positive for glycolysis. Combined with the results of the genomewide covariance alignment, it was known that strain 18B had a certain evolutionary relationship with O. jilunii 14-2AT . The cellulose-degradation ability was found that the cellulase activity of 18B was up to 82.14+0.99 -9.90 U/L at 37℃, 200 r/min until the 5th d. Meanwhile, the enzyme activity could be maintained without degradation under the incubation conditions with sodium carboxymethyl cellulose as the only carbon source and only inorganic nitrogen source added. O. jilunii 14-2AT had no cellulose degrading ability and could not survive in a culture environment where sodium carboxymethylcellulose was the only organic carbon source. The results of whole genome sequencing showed that there were cellulase genes in the genome of strain 18B. The cellulase genes were heterologous expressed in Escherichia coli, and the degradation ability of the expressed products was tested. The results showed that the cellulase genes were active. The above results finally identified strain 18B as a new physiological strain of O. jilunii with cellulase activity. [ABSTRACT FROM AUTHOR]