Isolation of Glucoamylase from Aspergillus Niger to Produce Liquid Sugar from Tapioca Flour

Abstract

This study aims to isolate the glucoamylase enzyme from Aspergillus niger to produce liquid sugar from tapioca flour. Enzymes are produced in a batch system laboratory-scale bioreactor. The fermentation substrate in an agar medium modified with the addition of starch. Fermentation was carried out for 168 hours at room temperature with an agitation speed of 120 rpm. The manufacture of liquid sugar is done by adding an enzyme as much as 0.3; 0.4; and 0.5 ml while the substrate concentration was varied by 20%; 30%; and 40%. The results showed that A. niger produce extracellular enzymes such as amylase and glucoamylase, particulary at exponential phase and the initial stationary phase. Enzymatic hydrolysis of starch consists of two stages, namely liquification and saccharification. In the liquification process, the enzyme α-amylase is used to break down starch containing amylose and amylopectin into dextrins. Next in the second stage is the saccharification process, where dextrin is hydrolyzed into glucose with the help of the glucoamylase enzyme. Optimal liquid sugar production can be done by adding 0.5 mL of crude enzyme extract at 30% (w/v) tapioca concentration. Further research is recommended to carry out enzyme purification to produce liquid sugar products with higher sugar purity.