Isolation, identification and in vivo colonization of free gossypol-degrading strain.

The efficient free gossypol-degrading strains were isolated and screened from quinoa stem leaf and tomato rod, to provide an excellent strain for biological detoxification of cottonseed meal. The free gossypol-degrading and protease-producing ability of the screened strains were tested, and in vivo colonization ability was further investigated by simulated gastric juice and simulated intestinal fluid tolerance tests, as well as antibiotics sensitivity test and surface characteristics test. The screened strain was identified by morphological observation, physiological and biochemical test and 16S rDNA sequence analysis. The results showed that a Bacillus strain with efficient free gossypol-degrading was obtained and numbered as S-77, with the free gossypol removal rate of 81.30% and the protease activity of 767.27 U/g. The strain S-77 was identified as Bacillus toyonensis, which was resistant to simulated gastric juice and intestinal fluid and had the ability to better adhere to the host intestinal parietal cells. The strain...