Optimization of fermentation conditions for green pigment production from Bacillus cereus M161 (MTCC 5521) and its pharmacological application

Optimal culture conditions for the production of green pigment was investigated. The optimal culture condition for the production of an extracellular green pigment by growing Bacillus cereus M-16(1) (MTCC 5521) in a complex medium containing (g l(-1)) Peptone-4.0, Beef Extract-9.0, NaCl-7.0, MgSO4 center dot 7H(2)O-1.0 and KH2PO4-5.0 was as follows pH-7.0 at 30 degrees C for 72 h in a 5 l fermenter. Aeration rate and agitator speed had no effect on the pigment production. Thin layer chromatogram of the pigment extracted from the fermented broth with chloroform on silica gel GF254 using ethyl acetate and hexane (1:1) as solvent showed three fractions. The major fraction (C-3) was separated out and identified as 9-methyl-1, 4, 5, 8-tetra-azaphenanthrene. Acute toxicity test revealed the nontoxic nature upto a dose of 2000 mg kg(-1), b.wt., of mice. MTT assay showed the cytotoxic nature in HL60 cells having an IC50 of 2.47 mmol. So, this biopigment may have application in food, textile colorant and pharmaceutical industry.