Characterization of natural therapeutic compounds producing novel bacterial strains isolated from Hyderabad, India

Natural products (NPs) are secondary metabolites that exert their biological effects within and on other organisms. Bacteria are considered potent producers of bioactive natural compounds, due to their versatile biocatalytic activity. The present study aims to isolate, identify, and analyze four novel bacterial strains that have the potential to produce NPs. The novelty was determined via taxonomical assessment using various biochemical and quantitative antagonistic screening assays. 16S rRNA molecular characterization and bioinformatics analysis identified the isolates as Klebsiella pneumoniae strain ABSKSLAB01, Klebsiella quasipneumonia strain ABSKSLAB02, Streptomyces minutiscleroticus strain ABSKSLAB03, and Streptomyces peucetius strain ABSKSLAB04. Their bacterial sequences were deposited in the GenBank database with accession numbers 'OP597532', 'OP597545', 'OQ061473', and 'PP086938', respectively. Among all the bacterial strains, ABSKSLAB04 demonstrated the highest antagonistic activity and the potential to produce NPs. Further optimization studies using the OVAT approach and statistical investigations via Plackett-Burman, RSM-Box-Behnken design, and artificial neural network rendered the optimized culture conditions to produce NPs: pH 7 ± 1.2, temperature 40 ± 5 °C, and inositol concentration of 5.5 ± 1.5, resulting in maximum antagonistic activity of 29.81 mm. The ANN model reflected superior predictive capacity compared to the RSM model with enhanced statistical metrics: R² (92.23%), MSE (0.0277), and RMSE (0.1477). ANN optimized production yield was measured at 580 mg/L, reflecting a 1.57-fold enhancement over the pre-optimized conditions (370 mg/L), and a 1.22-fold improvement compared to the RSM model (450 mg/L). This highlighted the ANN model's robustness in modeling complex nonlinear relationships and optimizing the bioprocess parameters with higher fidelity. Therefore, the results from the study conclude the potential of the designated bacterial strain (ABSKSLAB04) to produce NPs with enhanced antimicrobial and antineoplastic characteristics. The strain can further be utilized in biotechnological paradigms by scaling up in the pharmaceutical and industrial sectors for therapeutic applications.