A study on enhanced production of 3-demethylated colchicine by a novel strain of Bacillus endophyticus isolated from rhizospheric soils of Gloriosa superba

Abstract

A native strain of Bacillus endophyticus, PC was found to be effective in demethylation of colchicine. The strain was isolated from rhizospheric soils of Gloriosa superba from Erode, Tamilnadu, and was grown in optimised conditions of carbon and nitrogen. To intensify the demethylation, the strain was enriched and grown for 15 generations starting from low (0.5 mg/ml) to very high (10 mg/ml) concentrations of colchicine. Owing to enrichment, B. endophyticus showed an MIC of 25 mg/ml, and notable activity of demethylation of colchicine. Maximum production was observed at idiophase level, wherein PC produced around 71.97% of 3-DMC. Supplementary studies with the strain B. endophyticus PC proved the adverse effects of colchicine on the metabolic and structural portrait of cells. There was major variance in the cell shape and size, including the clipping of thickness of plasma membrane and cell wall. The number of polyhydroxybutyrate (PHB) rich inclusion bodies were found to be enhanced, suggesting their portrayal in activation of P450-BM3 enzyme which initiates demethylation.

Keywords:

• Microbial transformation
• colchicine
• 3-Demethyl colchicine
• Bacillus sp

Acknowledgement

The authors are thankful to Dr. Venil Sumantran, Scientific Advisor, Dr. APJ Abdul Kalam Centre of Excellence in Innovation and Entrepreneurship for her scientific inputs. The identification of bacterial strain by Chromous India Pvt. Ltd., Bangalore and SEM and TEM analysis by Sophisticated Test and Instrumentation Centre, Kochi India is thankfully acknowledged.

Disclosure statement

The above authors mentioned in the manuscript do not have any conflict of interest.

Additional information

Funding

The authors sincerely acknowledge Science and Engineering Research Board (SERB) for the financial support [Project no. YSS/2015/000614].