Rhizopus glucoamylase from

SoKd substrate fermentation using agricultural wastes was considered to be used for the production of both enzymes in order to reduce the production costs. Production of glucoamylase from Aspergillus niger J8 was reported (1,3). This report concerned on the production of pectinases from Rhizopus sp. 26R in solid substrates composting of agricultural wastes, optimization of the conditions for pectinases production in solid substrates and the estimation of the production cost. 

The efficiency in raw cassava starch hydrolyzation of pectinases from Rhizopus sp. 26R compared with a commercial pectinase when mixed with Glucoamylase from Aspergillus niger J8. 

Pure glucoamylase from Rhizopus nivetis from Aspergillus niger glucose 90 n.d. 80-100 65-75 80-100 40-50... 

Kitahara, K., Suganuma, T., and Nagahama, T. 1996. Susceptibility of amylose-lipid complexes to hydrolysis by glucoamylase from Rhizopus niveus. Cereal Chem., 73(4), 428. 

Glucoamylase from Rhizopus niveus has been shown to have an exo action on (l-> 3)-o - and (1 6)-a-D-glucan linkages as well as on malto-oligo-saccharides. ... 

The Michaelis constant and maximal velocity of a-amylase-free glucoamylase from Rhizopus delemar have been shown to decrease with increasing periodate oxidation of amylose.These kinetic features have been explained on the basis of competitive inhibition by the oxidized non-reducing end of the (1 4)-o -D-... 

The hydrolysis of maltose by glucoamylase from Rhizopus niveus was carried out in the presence an d absence of dextran sulphate, which are the components of supports of immobilized enzymes.The interaction between dextran and the enzyme was observed by fluorescence spectrophotometry. The kinetic and fluorescence experiments indicated that dextran became bound to glucoamylase and was apparently a non-competitive inhibitor of the enzyme. The dissociation constant of the enzyme-dextran complex was estimated to be 34%. The reaction rate was hardly affected at pH 4.0 and 4.5 by addition of dextran sulphate, whereas the kinetic parameters depended considerably on the concentration of dextran sulphate at pH 3.5. These findings indicated that there might exist some interactions between the enzyme and dextran sulphate. 

Pectinase from Rhizopus sp. 26R showed high efficiency in enhancing the digestion of raw starch from whole cassava tuber when it was mixed with the glucoamylase. At the 1 hour of the reaction, the mixed enzymes gave the most efficient digestibility with hydrolyzation rate twice faster, than that when glucoamylase was used alone and about 3 times faster than when pectinases... 

Figure 10 showed that using pectinases from Rhizopus sp. 26R with glucoamylase, in the first half hour, the efficiency of starch hydrolyzation could be increased approx. 2.6 times more than when using only glucoamylase. In the 2nd, 4th,6th and 8th hour, the hydrolyzation was 2, 1.6, l.Sand 1.4 times more efficient than using only glucoamylase, respectively. 

The pectinases produced in solid substrates from Rhizopus sp. 26R showed the efficiency in enhancing the activity of the glucoamylase in digestion of raw-ground-cassava tuber higher than that of the commercial one. 

Fig, 3,—Action of Rhizopus niveus Glucoamylase (free from oIpho-Amylase)... 

Glucose (from starch) Glucoamylase (Amyloglucosidase) A. niger, Rhizopus nivem... 

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