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Immobilization of Aspergillus oryzae with κ-Carrageenan for Soybean Oligosaccharide Hydrolysis
S. K. Praveen Kumar,V. H. Mulimani 한국식품과학회 2011 Food Science and Biotechnology Vol.20 No.6
The immobilized Aspergillus oryzae spores in κ-carrageenan were used for production of α-galactosidase. The immobilized cells could be used up to 5 repeated cycles for enzyme production. They were employed for raffinose family oligosaccharides (RFO) hydrolysis in batch, repeated batch, and continuous operations after 5days of fermentation. In batch mode, 65, 73, and 80% of RFOs were hydrolyzed after 3, 6, and 12 h, respectively; in repeated batch; 70, 63, 52, and 45% were hydrolyzed in 1,2, 3, and 4 repeated cycles. In the fluidized bed reactor, 65,58, 53, 48, and 44% RFOs were hydrolyzed at flow rates of 25, 50, 75, 100, and 125 mL/h respectively. The κ-carrageenan beads maintain good mechanical strength up to 4 repeated uses for RFO hydrolysis in soymilk, and their use in the hydrolysis of RFOs of soybean is a promising solution to overcome flatulence and to increase consumption of soy products.
Aravind Goud G. Patil,Veerappa H. Mulimani 한국생물공학회 2008 Biotechnology and Bioprocess Engineering Vol.13 No.3
Consumption of soymilk and soybean derived foods has been hampered due to the presence of RFOs (raffinose family oligosaccharides). Soy-based foods free from RFOs have positive impact on their acceptance as protein rich food. α-Galactosidase was entrapped in PVA (polyvinyl alcohol) cross linked with boric acid. Immobilized enzyme showed shift in optimum pH of 0.4 units and the activity yield of the immobilized α-galactosidase was found to be 76%. Immobilized enzyme was used to reduce RFOs in soymilk. In batch reaction after 12 h incubation soluble and immobilized enzyme showed 92 and 83% reduction of RFOs in soymilk, respectively. In repeated batch experiments immobilized enzyme showed 64% of its hydrolyzing activity after 6th cycle. PVA-immobilized α-galactosidase in fluidized bed reactor showed highest reduction (92%) of RFOs at a flow rate of 30 mL/h. The results of this study are interesting for their use in food processing industry.
( Patil Aravind Goud G. ),( Praveen Kumar S. K. ),( Veerappa H. Mulimani ),( Yaligara Veeranagouda ),( Kyoung Lee ) 한국미생물 · 생명공학회 2010 Journal of microbiology and biotechnology Vol.20 No.11
A bacterial strain capable of producing extracellular α- galactosidase was isolated from a sample of sugarcane industrial waste. Microbiological, physiological, and biochemical studies revealed that the isolate belonged to Bacillus sp. Furthermore, based on a 16S rDNA sequence analysis, the new isolate was identified as Bacillus megaterium VHM1. The production of α-galactosidase was optimized based on various physical culture conditions. Guar gum and yeast extract acted as the best carbon and nitrogen sources, respectively. The optimum pH was 7.5 and the enzyme remained stable over a pH range of 5-9. The enzyme was optimally active at 55oC and thermostable with a half-life of 120 min, yet lost 90% of its residual activity within 120 min at 60oC. One mM concentrations of Ag2, Cu2, and Hg2+ strongly inhibited the α-galactosidase, whereas the metal ions Fe2, Mn2+, and Mg2+ had no effect on the α-galactosidase activity, and Zn2+, Ni2+, and Ca2+ reduced the enzyme activity slightly. When treated with the B. megaterium VHM1 enzyme, the flatulence-causing sugars in soymilk were completely hydrolyzed within 1.5 h.