Journal of Petroleum & Environmental Biotechnology

Bacillus pumilus like micro-organism: A novel and promising ectoine producer isolated from the marine niche

Chirag D. Desai and Rekha S. Singhal

: Agrotechnol

Abstract:

Ectoine, a zwitterionic, low molecular weight compatible solute found in halophiles offers numerous potential biotechnological applications. There are many reported ectoine producers, but the marine environment offers possibilities of better and other unknown producers of ectoine. During our work on screening potential ectoine producers along the Western coast of India, we isolated and identified an aerobic culture biochemically and using molecular technique as Bacilus pumilus. This culture was used for ectoine production by one-factor-at-a-time method and subsequently by Response Surface Methodology. Ectoine production increased from 15.3 mg/L in the initial medium to 99.62 mg/L in the statistically optimized medium containing 55.0 mM glucose, 0.6 % (w/v) mycological peptone, 0.1 % (w/v) ammonium chloride and 3 M sodium chloride. Supplementation of the RSM optimized medium by 4 mM aspartic acid and further optimization of the amino acid enriched medium by Evolutionary Operation (EVOP) yielded 279.68 mg/L ectoine with 70 mM glucose, 2.0 M NaCl and 4.0 mM aspartic acid. Further, the effect of a combined addition of sodium chloride and magnesium chloride and ethylene glycol/glycerol/proline/sucrose on production of ectoine was checked. A second round of EVOP optimization increased the ectoine to 552.61 mg/L with 2.25 M NaCl, 0.75 M MgCl 2 and 1.25 M glycerol as the final optimized medium components. Using this medium in a lab-scale bioreactor increased the ectoine production to 956.06 mg/L. Further work on identifying the gene responsible for the ectoine synthesis in this organism with an aim to enhance the productivity of the culture is under progress

Biography :

Chirag D. Desai is pursuing his Ph. D. (Science) Biotechnology degree under the guidance of Prof. Rekha S. Singhal, Professor of Food Technology, Department of Food Engineering and Technology, Institute of Chemical Technology, Matunga (E), Mumbai-400019, India. The authors are working on the topic ?Studies on fermentative production and downstream processing of ectoine?