Complete genome of Nakamurella sp. PAMC28650: genomic insights into its environmental adaptation and biotechnological potential.

The mechanisms underlying the survival of bacteria in low temperature and high radiation are not yet fully understood. Nakamurella sp. PAMC28650 was isolated from a glacier of Rwenzori Mountain, Uganda, which species belonged to Nakamurella genus based on 16S rRNA phylogeny, ANI (average nucleotide identity), and BLAST Ring Image Generator (BRIG) analysis among Frankineae suborder. We conducted the whole genome sequencing and comparative genomics of Nakamurella sp. PAMC28650, to understand the genomic features pertaining to survival in cold environment, along with high UV (ultraviolet) radiation. This study highlights the role of polysaccharide in cold adaptation, mining of the UV protection-related secondary metabolites and other related to cold adaptation mechanism through different bioinformatics tools, and providing a brief overview of the genes present in DNA repair systems. Nakamurella sp. PAMC28650 contained glycogen and cellulose metabolism pathways, mycosporine-like amino acids and isorenieratene-synthesizing gene cluster, and a number of DNA repair systems. Also, the genome analysis showed osmoregulation-related genes and cold shock proteins. We infer these genomic features are linked to bacterial survival in cold and UV radiation.

Genomic insight into O-demethylation of 4-methoxybenzoate by a two-component system from Amycolatopsis magusensis KCCM40447.

Cytochrome P450 monooxygenases perform a multitude of roles, including the generation of hydroxylated aromatic compounds that might be utilized by microorganisms for their survival. WGS data of Amycolatopsis magusensis KCCM40447 revealed a complete circular genome of 9,099,986 base pairs and functionally assigned 8601 protein-encoding genes. Genomic analysis confirmed that the gene for 4-methoxybenzoate monoxygenase (CYP199A35) was conserved in close proximity to the gene for 4-hydroxybenzoate transporter (PcaK). The co-localized genes encoding CYP199A35, and ferredoxin-NAD(P) reductase (Mbr) represent a two-component system for electron transfer. CYP199A35 was specific for O-demethylation of para O-methyl substituted benzoic acid derivatives, 4-methoxybenzoate (4 MB), and 4-methoxycinnamic acid (4MCA) using the native redox partner (Mbr); two-component system and non-physiological redox partners (Pdr/Pdx); three-component system. The catalytic efficiency for O-demethylation of 4 MB using Mbr and Pdr/Pdx was 0.02 ± 0.006 min-1 µM-1 and 0.07 ± 0.02 min-1 µM-1 respectively. Further, sequence annotation and function prediction by RAST and KEEG analysis revealed a complete catabolic pathway for the utilization of 4 MB by strain KCCM40447, which was also proved experimentally.

Identification and evaluation of CAZyme genes, along with functional characterization of a new GH46 chitosanase from Streptomyces sp. KCCM12257.

The genomic analysis of Streptomyces sp. KCCM12257 presented 233 CAZyme genes with a predominant glycosyl hydrolase family. This contributes degradation of various polysaccharides including chitin and chitosan, and other promising candidates for the production of different oligosaccharides. We screened the strain providing different polysaccharides as a sole source of carbon and strain KCCM12257, showed higher activity towards colloidal chitosan. Further, we identified and characterized a new chitosanase (MDI5907146) of GH46 family. There was no activity towards chitin, carboxymethylcellulose, or even with chitosan powder. This enzyme acts on colloidal chitosan and hydrolyzes it down into monoacetyl chitobiose, which consists of two glucosamine units with an acetyl group attached to them. The maximum enzyme activity was observed at pH 6.5 and 40 °C using colloidal chitosan as a substrate. The Co2+ metal ions almost double the reaction as compared to other metal ions. The dissociation constant (Km) and of colloidal chitosan (≥90 % and ≥75%DD) were 3.03 mg/ml and 5.01 mg/ml respectively, while maximum velocity (Vmax) values were found to be 36 mg/ml, and 30 µM/µg/min, respectively. Similarly, catalytic efficiency (Kcat/Km) of colloidal chitosan with ≥90 %DD was 1.9 fold higher than colloidal chitosan with ≥75%DD.