Comparative proteome analysis of alkaliphilic Bacillus sp. N16-5 grown on different carbon sources.

To determine the impact of carbohydrates on the metabolic pathway in alkaliphiles, proteomes were obtained from cultures containing different carbohydrates and were resolved on two-dimensional gel electrophoresis (2-DE). The proteomes were compared to determine differentially expressed proteins. A novel alkaliphilic bacterium (alkaliphilic Bacillus sp. N16-5 isolated from Wudunur Soda Lake, China) was isolated in media with five different carbon sources (glucose, mannose, galactose, arabinose, and xylose). Comparative proteome analysis identified 61 differentially expressed proteins, which were mainly involved in carbohydrate metabolism, amino acid transport, and metabolism, as well as energy production and conversion. The comparison was based on the draft genome sequence of strain N16-5. The abundance of enzymes involved in central metabolism was significantly changed when exposed to various carbohydrates. Notably, catabolite control protein A (CcpA) was up-regulated under all carbon sources compared with glucose. In addition, pentose exhibited a stronger effect than hexose in CcpA-mediated carbon catabolite repression. These results provided a fundamental understanding of carbohydrate metabolism in alkaliphiles.