Growth Phases of Some Antibiotics Producing Streptomyces and their Identification

Abstract

The growth phases of five cultures of antibiotic producing Streptomyces isolated from western region, Saudi Arabia were studied special al reference to their potentiality to excrete antibiotics. It was found that these organisms grew exponentially during the first 4 to 7 days of incubation. The highest specific growth "rate was observed in the case of Streptomyces MY18 being 0.48 day-l (1.44 days doubling time). This isolate also showed the highest inhibition zone against Staph. aureus as compared with the other four Streptomyces isolates. This antagonistic effect was more pronounced at the last five d~ys of incubation (stationary phase). Morphological, cultural and physiological properties of most active antibiotic producers revealed that Streptomyces MY18 and Streptomyces MR13 are strains of S. aureofaciens and S. reseviolaceus respectively.

Optimization of Culture Conditions for Production of Bioactive Metabolites by <i>Streptomyces</i> spp. Isolated from Soil

“…It has been reported that two phases are observed during the propagation of antibiotic producers. The first phase (trophophase) is characterized by rapid growth (biomass production) and the second phase (idiophase) is characterized by a slow growth and maximal productivity of antibiotics [30]. For isolate R3 and Y8, a similar result was recorded where maximum antibiotic activity could be seen on eighth and tenth day and then it was almost stable.…”

Effects of Cultural Conditions in Enhancing the Production of Anti-MRSA Activity of Lasiodiplodia pseudotheobromae IBRL OS-64, an Endophytic Fungus Isolated from Leaf of Ocimum sanctum L. in Submerged Fermentation System

“…These unfavorable conditions are believed to adversely affect the expression of microbial secondary metabolites (Griffin, 1995). According to Sejiny (1991), during the propagation of antibiotics producers, two phases were observed which were trophophase and idiophase. Trophophase is characterized by rapid growth of microbial cells producing biomass and during the idiophase, slow microbial growth was observed and maximal antibiotic production was obtained.…”

Isolation, characterization, anti-MRSA evaluation, and in-silico multi-target anti-microbial validations of actinomycin X2 and actinomycin D produced by novel Streptomyces smyrnaeus UKAQ_23

“…The effects of media constituents and fermentation conditions on antibiotic production were determined by varying the one factor at a time and base fermentation conditions were kept constant, i.e ., pH 6.5, temperature 30 °C, carbon source 1% w/v, nitrogen source 0.5% w/v, NaCl 0.50% w/v, inoculum 5% v/w, agar 1.5% w/v, and incubation period of 7 days. After completing each set of fermentation, the yield of antimicrobial extract was measured in mg/kg of fermented agar 53 , 61 , 62 , 73 , 74 .…”