Rice bran as an efficient substrate for laccase, production from thermotolerant basidiomycete Coriolus versicolor strain RC3

Suitable substrates for laccase production by the thermotolerant basidiomycete Coriolus versicolor strain RC3 were screened using solid and liquid media. In liquid basal medium, 1%(w/v) rice bran as a carbon source was found to be the most efficient substrate for laccase production compared to 1%(w/v) glucose, wheat bran and rice straw meal. After 15 days cultivation at 37degreesC in shake flask culture, the extracellular laccase activity was found to be 0.22 U/ml with rice bran, while 0.09, 0.01 and 0.01 U/ml were obtained from wheat bran, glucose and rice straw meal, respectively. The optimum concentration of rice bran was 1%(w/v). Comparison of laccase production on three different selected solid substrates including rubber wood meal (Heavea sp.), Hang nok yoong wood meal (Delonix regia) and rice bran, were carried out using 5g of solid substrate supplemented with 15 ml of distilled water and cultivated at 37degreesC in the dark for 30 days. Laccase production from C. versicolor strain RC3 was 1.98, 0.06 and 0.07 U/g substrate from rice bran, rubber wood meal and Hang nok yoong wood meal, respectively. The highest laccase productivity with rice bran in liquid medium was 22 U/g substrate at 15 days cultivation. This was 11 times higher than the maximum activity obtained at 3 0 days on, solid substrate cultivation.