Isolation and characterization of amylase from Aspergillus flavus var. columnaris, a soy sauce koji mould
1986
Dharmsthiti, S.C. | Flegel, W. | Bhumiratana, A. (Mahidol University, Bangkok (Thailand). Department of Microbiology)
Aspergillus flavus var. columnaris ATCC 44310, a soy sauce koji mould was found to produce two different types of glucoamylase (GI and GII) and an alpha-amylase (AI). The alpha-amylase represented one of the major extracellular enzymes produced by this fungus. The partially purified GI, GII and AI had pH optima of 4.0, 5.0, respectively, and the temperature optima of 50, 55 and 55 C respectively. The activities of the amylolytic enzymes were stimulated by a low concentration of NaCl. However, all were inhibited by high concentrations of NaCl. The kinetics of amylolytic enzyme production in soy sauce koji indicated that enzyme activity became detectable at 20 h after mould inoculation and r1153eached a maximum level of 8.4 x 10(4) U/gm dry weight of koji at 38 h, thereafter. Thus, the usual practice of terminating industrial koji was 48 h after inoculation would normally ensure that the maximum levels of amylases production had been rea
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