Full Length Research Paper

Optimization of cultural conditions for production of chitinase by Bacillus laterosporous MML2270 isolated from rice rhizosphere soil

V. Shanmugaiah¹, N. Mathivanan¹*, N. Balasubramanian² and P.T. Manoharan³

¹Biocontrol and Microbial Metabolites Lab, Centre for Advanced Studies in Botany, University of Madras, Guindy Campus, Chennai – 600025, India.

²Centre for Advanced Studies Botany, University of Madras, India.

³Department of Botany, Vivekananda College, Thiruvedakam West-625217, Tamil Nadu, India.

*Corresponding author.  E-mail: prabhamathi@yahoo.com. Tel: +91-44-22350401 (O); +91-44-42022789 (R). Fax: +91-44-22352494.

Accepted 5 February, 2008

A total of 39 chitinolytic bacteria were isolated from 77 rhizosphere soil samples collected from different crop fields in Tamil Nadu state, India. Among them, a strain designated as MML2270, which produced highest chitinolytic activity in primary and secondary screening in colloidal chitin agar was selected and later identified as Bacillus laterosporous. The production of chitinase by B. laterosporous was optimized using different growth media, substrate concentrations, pH, temperature and incubation period. The maximum chitinase production was observed in yeast nitrogen based medium (YNB) amended with 0.3% colloidal chitin at pH 8.0 and 35°C after four days of inoculation. Under this optimized growth condition, B. laterosporous MML2270 produced a total chitinase activity of 59.05 units/ml as against only 19.7 units/ml in the initial YNB medium stage, which is a three-fold increase.

Key words: Chitinolytic bacteria, Bacillus laterosporous, chitinase, culture conditions.