title: Enhanced production of antimicrobial compounds by three salt-tolerant actinobacterial strains isolated from the Sundarbans in a niche-mimic bioreactor.
abstract: A novel reactor system, the rotating disk bioreactor (RDBR), was used to mimic the niche environmental conditions of three salt-tolerant estuarine actinobacteria isolated from the Sundarbans region off the Bay of Bengal, designated MS310 (99% similar in its 16S rRNA gene sequence to Streptomyces parvallus), MS3/20 and MS1/7. The RDBR, operated at a rotational speed of one revolution per day, 50% submergence of discs, aeration rate of 1.0 vvm, and with a sucrose-containing medium, faithfully mimicked the intertidal estuarine habitat of these marine isolates, and supported biofilm formation and production of antimicrobial metabolites-in particular, actinomycin D by MS310. Onset of antibiotic production by MS310 occurs at 20 h in the RDBR compared to 55 h in a conventional stirred-tank bioreactor (STBR). Furthermore, peak antimicrobial activity is attained much earlier in the RDBR with MS310 (at 45 h) than that reported with a terrestrial strain of S. parvallus grown in a STBR (at 144 h). Peak antimicrobial activity of metabolites produced by MS1/7 and MS3/20 were also attained earlier in the RDBR (at 25 and 12 h, respectively) than in a STBR (at 80 and 28 h, respectively). Antibiotic synthesis in the three isolates, in general, appears to be associated with their growth. Overall, the RDBR may be considered the preferred alternative to the STBR for production of antimicrobials by biofilm-forming estuarine bacteria for its much higher surface/volume ratio, lower costs, and easy operability.
authors: School of Environmental Studies, Jadavpur University, Kolkata 700 032, India.
authors: Sreyashi
authors: S
authors: Sarkar
authors: Malay
authors: M
authors: Saha
authors: Debashis
authors: D
authors: Roy
authors: Parasuraman
authors: P
authors: Jaisankar
authors: Satadal
authors: S
authors: Das
authors: Lalita
authors: L
authors: Gauri Roy
authors: Ratan
authors: R
authors: Gachhui
authors: Tuhinadri
authors: T
authors: Sen
authors: Joydeep
authors: J
authors: Mukherjee
mesh_terms: D039903:Actinobacteria / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D000890:Anti-Infective Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D019149:Bioreactors; D003609:Dactinomycin / Q000737:chemistry / Q000378:metabolism / Q000494:pharmacology; D019015:Geologic Sediments / Q000382:microbiology; D007194:India; D008826:Microbial Sensitivity Tests; D055049:Salt Tolerance / Q000502:physiology*; D013211:Staphylococcus aureus / Q000187:drug effects; D013997:Time Factors
chemical_list: D000890:Anti-Infective Agents; D003609:Dactinomycin