Complete genome sequencing and identification of fiber-degrading potential in Bacillus amyloliquefaciencs strain TL106 from the Tibetan pig

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Background Cellulolytic microorganisms are considered a key player in the degradation of feed fiber. These microorganisms can be isolated from various environments, such as animal gut, plant surfaces, soil and oceans. New Bacillus amyloliquefaciens strain TL106 isolated from healthy Tibetan pigs’ faeces, which secretes cellulase and shows strong antimicrobial activity in mice. So, in this study, to better understand a B. amyloliquefaciens strain with cellulose degradation ability, the genome of the strain TL106 was completely sequenced and analyzed. In addition, we also explored the cellulose degradation ability of strain TL106 in vitro. Results The present study performed third generation high-throughput DNA sequencing technology and enzymatic hydrolysis in vitro to analyze the complete genome and cellulose degradation ability of B. amyloliquefaciens TL106. The TL106 consisted of one circular chromosome of 3,980,960 bp and one plasmid of 16,916 bp, the gene total length was 3.99 Mb and a total of 4,130 genes predicted. There were also some cellulase and hemicellulase genes detected, including β-glucosidase, endoglucanase, ß-glucanase and xylanase genes. Additionally, the activities of amylase (20.25 U/mL), cellulase (20.86 U/mL), xylanase (39.71 U/mL) and β-glucanase (36.13 U/mL) in the fermentation supernatant of TL106 strain were higher. In the study of degradation characteristics, we found that strain TL106 had a better degradation effect on crude fiber, neutral detergent fiber, acid detergent fiber, starch, arabinoxylan and β-glucan of wheat and highland barley. Conclusions B. amyloliquefaciens TL106 includes a variety of cellulase and hemicellulase genes, can produce carbohydrate-active enzymes, amylase, cellulase, xylanase and β-glucanase. Additionally, the bacterial solution of strain TL106 can degrade the fiber fraction and non-starch polysaccharides (arabinoxylans and β-glucan) of wheat and highland barley. The present study demonstrated that the degradability of strain TL106 to crude fiber is strong, which may have a good application prospect in the feed industry.