Alkalimonas mucilaginosa sp. nov. and Alkalimonas cellulosilytica sp. nov. isolated from alkaline Lonar lake, India.

Abstract

Two alkaliphilic, Gram-stain-negative bacterial strains (MEB004^T and MEB108^T) were isolated from water samples collected from Lonar lake, India. The phylogenetic analysis of their 16S rRNA gene sequences showed the highest similarity to A. delamerensis DSM 18314^T (98.4%), followed by A. amylolytica DSM 18337^T and A. collagenimarina JCM 14267^T (97.9%). The genome sizes of strains MEB004^T and MEB108^T were determined to be 3,858,702 and 4,029,814 bp, respectively, with genomic DNA G + C contents of 51.4 and 51.9%. Average Nucleotide Identity, DNA-DNA Hybridization and Amino Acid Identity values between strains (MEB004^T and MEB108^T) and A. amylolytica DSM 18337^T were (82.3 and 85.5), (25.0 and 29.2) and (86.7 and 90.2%). Both novel strains produced industrially important enzymes, such as amylase, lipase, cellulase, caseinase, and chitinase at pH 10 evidenced by the genomic presence of carbohydrate-active enzymes encoding genes. Genomic analyses further identified pH tolerance genes, affirming their adaptation to alkaline Lonar Lake. Dominant fatty acids were Summed feature 8 (C_18:1 ω7c and/or C_18:1 ω6c), C_16:0, Summed feature 3, Sum In Feature 2 and C_12:0 3OH. The prevalent polar lipids included phosphatidyl ethanolamine, phosphatidyl glycerol, and diphosphatidyl glycerol. The major respiratory quinone was ubiquinone-8. Based on the polyphasic data, we propose the classification of strains MEB004^T and MEB108^T as novel species within the genus Alkalimonas assigning the names Alkalimonas mucilaginosa sp. nov. and Alkalimonas cellulosilytica sp. nov., respectively. The type strains are MEB004^T (= MCC 5208^T = JCM 35954^T = NCIMB 15460^T) and MEB108^T (= MCC 5330^T = JCM 35955^T = NCIMB 15461^T).