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.
Niladevi
Kizhakkedathu Narayanan
KN
Biotechnology Division, Regional Research Laboratory (CSIR), Trivandrum, India.
Sukumaran
Rajeev Kumar
RK
Prema
Parukuttyamma
P
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