Characterization of Streptomyces sp. KB1 and its cultural optimization for bioactive compounds production

Abstract

Background Bioactive compounds (BCs) from natural resources have been extensively studied because of their use as models in the development of novel and important medical and biopreservative agents. One important source of BCs is microorganisms, particularly terrestrial bacteria of the order Actinomycetales. Methods We characterized Streptomyces sp. KB1 by observing its morphology, physiology, and growth on different media using biochemical tests, optimizing cultural conditions by changing one independent variable at a time. Results Streptomyces sp. KB1 (TISTR 2304) is a gram-positive and long filamentous bacteria that forms straight to flexuous (rectiflexibile) chains of globose-shaped and smooth-surfaced spores. It can grow under aerobic condition s only at a temperature range of 25–37 °C and initial pH range of 5–10 in the presence of sodium chloride 4% (w/v). Therefore, it is considered an obligate aerobe, mesophilic, neutralophilic, and moderately halophilic bacteria. The isolate grew well on peptone-yeast extract iron, Luria Bertani (LB), and a half-formula of LB (LB/2), but could not grow on MacConkey agar. It utilized fructose, mannose, glucose, and lactose as its carbon source along with acid production and showed positive reactions to casein hydrolysis, gelatin liquefaction, nitrate reduction, urease, and catalase production. Streptomyces sp. KB1 (TISTR 2304) could produce the maximum number of BCs when 1% of its starter was cultivated in a 1,000 ml baffled flask containing 200 ml of LB/2 broth with its initial pH adjusted to 7 with no supplemental carbon source, nitrogen source, NaCl, or trace element at 30 °C, shaken at 200 rpm in an incubator for 4 days.

Optimization of growth conditions of Streptomyces sp in Rock phosphate beneficiation process

“…Initial pH and temperature of Streptomyces sp. studied growth is consistent with the studies of Gunjal and Bhagat (2022) and Lertcanawanichakul and Sahabuddeen (2023), who described the growth conditions of Streptomyces in which the ideal growth temperature is 25-35°C and pH 6.5-8.0. These developmental conditions lead to active enzymatic systems to complete oxidation processes or to use organic compounds as the primary source of carbon.…”