Insights into xylan degradation and haloalkaline adaptation through whole-genome analysis of Alkalitalea saponilacus, an anaerobic haloalkaliphilic bacterium capable of secreting novel halostable xylanase

Baisuo Zhao; Ziya Liao; Mark Holtzapple; Yanchun Yan; Haisheng Wang; Jun Li

Insights into xylan degradation and haloalkaline adaptation through whole-genome analysis of Alkalitalea saponilacus, an anaerobic haloalkaliphilic bacterium capable of secreting novel halostable xylanase

Joint Event on 14^th International Conference on Microbial Interactions & Microbial Ecology & 11^th Edition of International Conference on Advances in Microbiology and Public Health

August 19-20, 2019 Vienna, Austria

Baisuo Zhao, Ziya Liao, Mark Holtzapple, Yanchun Yan, Haisheng Wang and Jun Li

Graduate school of Chinese Academy of Agricultural Sciences, China
Texas A&M University, USA
Chinese Academy of Agricultural Sciences, China

Posters & Accepted Abstracts: J Med Microb Diagn

Abstract :

The obligately anaerobic haloalkaliphilic bacterium Alkalitalea saponilacus can use xylan as the sole carbon source and produce propionate as the main fermentation product. Using mixed carbon sources of 0.4% (w/v) sucrose and 0.1% (w/v) birch xylan, xylanase production from A. saponilacus was 3.2-fold greater than that of individual carbon sources of 0.5% (w/v) sucrose or 0.5% (w/v) birch xylan. The xylanse is halostable and exhibits optimal activity over a broad salt concentration (2�??6% NaCl). Its activity increased approximately 1.16-fold by adding 0.2% (v/v) Tween 20. To understand the potential genetic mechanisms of xylan degradation and molecular adaptation to saline-alkali extremes, the complete genome sequence of A. saponilacus was performed with the pacBio singlemolecule real-time (SMRT) and Illumina Misseq platforms. The genome contained one chromosome with a total size of 4,775,573 bps, and a G+C genomic content of 39.27%. Ten genes relating to the pathway for complete xylan degradation were systematically identified. Furthermore, various genes were predicted to be involved in isosmotic cytoplasm via the �??compatible-solutes strategy�?� and cytoplasmic pH homeostasis though the �??influx of hydrogen ions�?�. The halostable xylanase from A. saponilacusand its genomic sequence information provide some insight for potential applications in industry under double extreme conditions.