Screening and identification of xylanase-producing strains isolated from crayfish intestine

Abstract:

[Background] The intestinal microbes are the main driving force of crayfish to degrade cellulose and hemicellulose. [Objective] The study of the relative abundance of bacteria in the intestine provides theoretical support for revealing the role of intestinal microorganisms in the degradation of lignocellulose. [Methods] The diversity of intestinal bacteria was studied by Illumina MiSeq high-throughput sequencing, and xylanase production bacteria were isolated from crayfish intestine by plate screening method. [Results] Morphological and 16S rRNA gene molecular identification showed that all 4 strains belonged to Bacillus genus. The four strains were identified combining the physiological and biochemical characteristics. The results showed that the strain Z-3 was identified as Bacillus subtilis, strain Z-4 was Bacillus velezensis, strain Z-29 was Bacillus cereus, strain Z-30 was Bacillus altitudinis. The results of 16S rRNA gene high-throughput sequencing showed that: at the genus level, the intestinal bacteria of crayfish were mainly Candidatus Bacilloplasma, Bacteroides, Vibrio, Acinetobacter, Dysgonomonas, Tyzzerella 3, Aeromonas and Shewanella. [Conclusion] Crayfish had abundant bacterial resources in the intestine, and Bacillus bacteria played an important role in the degradation of lignocellulose.