小龙虾肠道产木聚糖酶细菌的分离与鉴定

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

摘要:

【背景】小龙虾肠道微生物是小龙虾降解纤维素和半纤维素的主要驱动力。【目的】研究肠道内细菌的相对丰度，为揭示肠道微生物在小龙虾纤维素降解过程中的作用提供理论支撑。【方法】采用纯培养法从小龙虾肠道筛选产木聚糖酶细菌，并且对小龙虾肠道细菌进行16S高通量测序。【结果】形态学和16S rRNA基因分子鉴定表明，筛选到的4株产木聚糖酶细菌均属于芽孢杆菌科芽孢杆菌属；结合进一步的生理生化特征鉴定，结果为：菌株Z-3为枯草芽孢杆菌(Bacillus subtilis)，菌株Z-4为贝莱斯芽孢杆菌(Bacillus velezensis)，菌株Z-29为蜡状芽孢杆菌(Bacillus cereus)，菌株Z-30为高地芽孢杆菌(Bacillus altitudinis)；16S rRNA基因高通量测序结果表明：在属水平上，小龙虾肠道细菌主要是Candidatus Bacilloplasma、拟杆菌属、弧菌属、不动杆菌属、Dysgonomonas、Tyzzerella 3、气单胞菌属和希瓦氏菌属细菌。【结论】小龙虾肠道内细菌资源丰富，且芽孢杆菌属细菌在木质纤维素降解过程中发挥一定功能。

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.