Utilization of rice straw for laccase production by Streptomyces psammoticus in solid-state fermentation.
Laccase production from a novel actinobacterial strain, Streptomyces psammoticus, MTCC 7334 was optimized in solid-state fermentation. The process parameters were initially optimized by the conventional "one factor at a time" approach, and the optimal levels of the factors that had considerable influence on enzyme production were identified by response surface methodology. Rice straw was identified as a suitable substrate for laccase production (17.3 U/g), followed by coffee pulp (15.8 U/g). Other optimized conditions were particle size, 500-1,000 mum (21.2 U/g); initial moisture content, 65% (26.8 U/g); pH of moistening solution, 8.0 (26.9 U/g); incubation temperature, 32 degrees C (27.6 U/g) and inoculum size, 1.5 x 10(7) CFU (33.8 U/g). Yeast extract served as the best nitrogen source (34.8 U/g). No enhancement in enzyme yield was observed with carbon supplementation. The level of yeast extract, inoculum size and copper sulphate were optimized statistically. Statistical optimization performed using a central composite design resulted in threefold increase in laccase activity (55.4 U/g) as compared to the unoptimized medium (17.3 U/g). The upgrading of fermented rice straw for fodder enhancement is also discussed briefly.
Biotechnology Division, Regional Research Laboratory (CSIR), Trivandrum, India.
Kizhakkedathu Narayanan
KN
Niladevi
Rajeev Kumar
RK
Sukumaran
Parukuttyamma
P
Prema
D003470:Culture Media / Q000737:chemistry*; D005285:Fermentation; D042845:Laccase / Q000096:biosynthesis*; D009584:Nitrogen / Q000378:metabolism; D012275:Oryza / Q000382:microbiology*; D010316:Particle Size; D018515:Plant Leaves / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology / Q000254:growth & development / Q000378:metabolism*; D013379:Substrate Specificity
D003470:Culture Media; D042845:Laccase; D009584:Nitrogen