Comparative genome-wide analysis of novel Streptomyces isolates RC1831 and RC1832: deciphering the role of functional carbohydrate (CAZy) active genes including chitinase for production of chitosan.

This work compares two bacterial isolates Streptomyces barkulensis RC1831 and Streptomyces chitinovorans RC1832 isolated from Chilika Lake sediments in Odisha, India, using whole-genome sequence analysis. According to the results of the genome analysis, the RC1831 genome has a chromosome with 6,383,258 bp (72.9% GC) and 6145 coding sequences and 66 RNA, while the RC1832 genome has a chromosome with 6,055,792 bp (73.1% GC) and 5824 coding sequences and 63 RNA. Further analysis of the carbohydrate active enzyme (CAZyme) revealed that RC1831 contains 78 glycoside hydrolase family genes, whereas RC1832 includes 50 glycoside hydrolases that have the potential to regulate the chitin-degrading enzymes. KAAS (KEGG Automatic Annotation Server) and AntiSMASH online tool V3.0.5 were used to identify a biosynthetic gene cluster in the isolated strain's genome. The detailed comparative analysis of the genes between the strains will help to gain better insight of chitin and other carbohydrate polymer degradation and secondary metabolite production in both the strains as well as the evolutionary relationship and possibilities of industrial application of these strains. Chitosan production might be explained by genes for the chitin breakdown pathway found in the genome sequence, but genes for later-stage conversion were not found. One significant biomolecule with a wide range of industrial uses is chitosan. Therefore, using these microbes to produce chitosan offers a viable waste disposal solution. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-024-03936-5.

Streptomyces griseoincarnatus strain RB7AG promotes Oryza sativa (var. swarna) growth under salt stress: mechanisms and potential applications.

The plant growth promoters (PGP) are the natural fertilizers that enhance the overall growth of the plant. We defined Streptomyces strain RB7AG as a potential halotolerant growth promoter and assessed its impact on rice plants' performance under salt stress. The organism was able to thrive at concentrations up to 10% of NaCl (w/v), optimal at 6% as measured by their cell growth, viability, and secondary metabolite production. Under salt stress, isolates were viable and generated Indolic chemicals and siderophores. The bacterized plants found to accumulate higher level of proline and antioxidant enzymes such as superoxide dismutase (SOD), peroxidase (POD), and catalases (CAT) that are subjected to salt stress, particularly those treated with Streptomyces strain RB7AG, which helps the plants to thrive in the adverse condition. The Streptomyces-treated plants were also found to have increased roots and shoots length, implying a systemic tolerance mechanism. The strain's formulations were created utilizing five organic and inorganic wastes as the carrier medium, and the shelf life of the propagules was also tracked. Vermicompost and vermiculite formulations were found to have the highest viable bacteria after 3 months of storage period.

Whole genome sequencing of a novel chitinolytic Streptomyces sp. RB7AG reveals it's chitosan production potential: optimization of the process through Taguchi experimental design.

This study reports about the De novo whole genome sequencing and analysis of a bacterial isolate Streptomyces sp. Strain. RB7AG, isolated from the sediments of Chilika Lake, Odisha, India. The genome report in this paper highlights a size of 7,708,681 bp and a GC content of 72.3%. It also consists of 7274 coding sequence, 66 tRNA and 4 rRNA. Furthermore, carbohydrate active enzyme analysis revealed that the strain RB7AG has 127 glycoside hydrolase family genes, which is well known for hydrolysis of glycosidic bond in complex sugars. Thus, exploiting these microorganisms for the production of chitosan can be an appropriate waste disposal method of choice. Chitosan being an important biomolecule that has various industrial applications. Hence, the study also sought to improve the culture conditions for the Streptomyces sp. strain RB7AG for generation, recovery, and characterization of chitosan. Utilizing the isolate, various low-cost nitrogen sources, including peptone, yeast extract, ammonium chloride, urea along with pH, media, metal ions and surfactant were assessed for chitosan synthesis. In this context, traditional methods such as One Factor One Time are more time consuming and expensive too. The current work aims to establish a methodology to optimize the degradation of chitin by the chitinolytic Streptomyces sp. strain RB7AG, isolated from lake sediment for the production of chitosan. More than one factor was considered at the time of experiments, and the knowledge was integrated into Taguchi statistical design to determine the contribution of the most important factors required to achieve the desired end product i.e. chitosan. Highest chitosan production (2.188 µg/ml) was observed in MSM media, 1.0% NaCl (w/v), 0.5% Yeast extract, 1% Ca2+ and 0.1% Tween 80 at pH 9. The whole genome analysis of RB7AG would help in determining the mechanism involved in the breakdown activity. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03613-z.

l-Asparaginase producing novel Streptomyces sp. HB2AG: optimization of process parameters and whole genome sequence analysis.

l-asparaginase (ASNase) is a key enzyme widely used as an anti-cancer drug and is also used in the pharmaceutical and food processing industries. This enzyme's applications are determined by its source and nature. The production of the enzyme through the fermentation process is also crucial for economic feasibility. Searching for a new potent microbial strain is necessary for increased ASNase synthesis. In this work, a potent strain was isolated from the sediment of Chilika Lake and selected for its high ASNase production potential. It was recognized following Bergey's manual of determinative and phylogenetic analysis was carried out by 16S rDNA sequencing. The isolated organism was Streptomyces sp. HB2AG. Additionally, a genome-wide analysis of HB2AG was performed. The result showed that the HB2AG genome possesses a chromosome with 6,099,956 bp and GC content of 74.0%. The whole genome analysis of the strain HB2AG revealed the presence of ASNase (ansA, ansB) and Asparagine synthase (asnB) in the HB2AG genome. Optimization of media composition is crucial for microbial growth and obtaining the desired end product. The current effort focuses on the Taguchi orthogonal design to determine optimum factor combinations that would allow the strain to produce maximum ASNase enzyme. Results showed that compared to unoptimized media, approximately 1.76-fold higher ASNase production was observed in Sea Water Luria Bertani (SWLB) media, pH-5, 0.5% (w/v) of lactose, 0.5% (w/v) of casein, 2.5% (w/v) NaCl, 1 mM Ca2+ and 0.1% Tween 80. Supplementary Information: The online version contains supplementary material available at 10.1007/s13205-023-03620-0.