Enhanced inulinase production in solid state fermentation by a mutant of the marine yeast Pichia guilliermondii using surface response methodology and inulin hydrolysis.
In order to isolate inulinase overproducers of the marine yeast Pichia guilliermondii, strain 1, cells were mutated by using UV light and LiCl(2). One mutant (M-30) with enhanced inulinase production was obtained. Response surface methodology (RSM) was used to optimize the medium compositions and cultivation conditions for inulinase production by the mutant in solid-state fermentation. The initial moisture, inoculum, the amount ratio of wheat bran to rice bran, temperature, pH for the maximum inulinase production by the mutant M-30 were found to be 60.5%, 2.5%, 0.42, 30 degrees C and 6.50, respectively. Under the optimized conditions, 455.9 U/grams of dry substrate (gds) of inulinase activity was reached in the solid state fermentation culture of the mutant M-30 whereas the predicted maximum inulinase activity of 459.2 U/gds was derived from RSM regression. Under the same conditions, its parent strain only produced 291.0 U/gds of inulinase activity. This is the highest inulinase activity produced by the yeast strains reported so far.
Guo
Ning
N
UNESCO Chinese Center of Marine Biotechnology, Ocean University of China, Yushan Road, No. 5, Qingdao, China.
Gong
Fang
F
Chi
Zhenming
Z
Sheng
Jun
J
Li
Jing
J
D003470:Culture Media / Q000378:metabolism; D046508:Culture Techniques; D005285:Fermentation; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D006026:Glycoside Hydrolases / Q000235:genetics / Q000378:metabolism*; D006868:Hydrolysis; D007328:Insulin / Q000378:metabolism*; D018020:Lithium Compounds / Q000737:chemistry; D016296:Mutagenesis; D009154:Mutation; D010843:Pichia / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification / Q000528:radiation effects; D012623:Seawater / Q000382:microbiology*; D014466:Ultraviolet Rays
D003470:Culture Media; D005656:Fungal Proteins; D007328:Insulin; D018020:Lithium Compounds; D006026:Glycoside Hydrolases; C023086:inulinase