Isolation and Identification of Potential Gossypol Degrading Fungal Strains from Cotton Growing Soil

Aim: To isolate and identify gossypol degrading fungal strains from cotton growing soil of Maharashtra and Andhra Pradesh States of India.

Study Design: Experimental study.

Place and Duration of the Study: Chemical and Biochemical Processing Division, ICAR-Central Institute for Research on Cotton Technology, Matunga (E), Mumbai – 400019, India during January to December 2014.

Methodology: The isolation of fungi from soil samples was done by enrichment culture technique using gossypol as a sole carbon and energy source. The fungal isolates were inoculated in cottonseed cake (CSK) and incubated for 48 h at 30°C. The isolates were screened for gossypol detoxification by estimating free and total gossypol level in the fermented CSK. The potential gossypol degrading isolates were identified by 18S rDNA analysis.

Results: Eight isolates (F1 to F8) were identified as potential gossypol degrading strains among the fifty nine isolates obtained. The new fungal isolates from F1 to F8 were identified as Aspergillus terreus (KP 264957.1), Lichithemia ramosa (KP 264961.1), Alternaria alternata (KP 264960.1), Fusarium equiseti (KP 26459.1), Fusarium chlamydospora (KP 264958.1), Fusarium sp. (KP 209032.1), Fusarium solani (KP 264956.1) and Fusarium thapsinum (KP 264962.1) respectively, based on 18S rDNA analysis. The maximum free and total gossypol reduction (%), 65.2 and 59.8 respectively was observed in Fusarium thapsinum (KP 264962.1) treated CSK. The protein content was higher in fungal treated than untreated CSK.

Conclusion: The present study identifies new fungal strains capable of degrading toxic compound, gossypol in cottonseed cake.