Lysobacter alkalisoli sp. nov., a chitin-degrading strain isolated from saline-alkaline soil

Abstract

Strains of <i>Lysobacter</i>, thought to play vital roles in the environment for their high enzyme production capacity, are ubiquitous in various ecosystems. During an analysis of bacterial diversity in saline soil, a Gram-stain-negative, aerobic, chitin-degrading bacterial strain, designated SJ-36^T, was isolated from saline-alkaline soil sampled at Tumd Right Banner, Inner Mongolia, PR China. Strain SJ-36^T grew at 4-40 °C (optimum, 30 °C), pH 5.0-10.0 (optimum, pH 7.0-8.0) and 0-6 % NaCl (optimum, 1.0 %). Oxidase and catalase activities were positive. A phylogenetic tree based on 16S rRNA gene sequences and the phylogenomic tree both showed that strain SJ-36^T formed a tight clade with <i>Lysobacter maris</i> KMU-14^T (sharing 97.6 % 16S rRNA gene similarity) and <i>Lysobacter aestuarii</i> S2-C^T (97.8 %). The major polar lipids of strain SJ-36^T were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, two unidentified lipids and one unidentified phospholipid. The major fatty acids were iso-C_{15 : 0} (37.5 %), summed feature 9 (14.0 %; iso-C_{17 : 1}ω9<i>c</i> and/or C_{16 : 0} 10-methyl) and iso-C_{11 : 0} (10.6 %). Q-8 was the predominant ubiquinone. Its genomic DNA G<i>+</i>C content was 66.6 mol%. The average nucleotide identity values of strain SJ-36^T to <i>L. maris</i> KMU-14^T, <i>L. aestuarii</i> S2-C^T and other type strains were 81.5, 79.1 and <79.0 %, respectively. The results of physiological, phenotypic and phylogenetic characterizations allowed the discrimination of strain SJ-36^T from its phylogenetic relatives. <i>Lysobacter alkalisoli</i> sp. nov. is therefore proposed with strain SJ-36^T (=CGMCC 1.16756^T=KCTC 43039^T) as the type strain.