Systematic comparison of gluconic acid optimization produced by Aspergillus using raw bioresources

Abstract

Several researchers discussed the influence of fungus and medium components on the gluconic acid quantity and quality. The new trend of research is focusing on finding cheaper alternatives for the carbon source used in the medium. Scientists cannot achieve this goal until the compatibility of medium and fungus is investigated. Thus, the current study aims to compare gluconic acid production by A.niger, A.fisheri and A.carneus systematically. Also, it examines the possible optimization of cultivation medium by using corn starch, banana must and molasses as cheap carbon source. The key parameters to identify the successful optimization are gluconic acid production, cell dry weight, biomass content and total reducing sugar. The result of the study showed that A. niger has 10.4 g/L gluconic acid at medium 2 which contains glucose. A pivotal proportional relation between the raw carbon source concentration and acid production was revealed. The most intriguing finding is the drastic reduction in the sugar content between 50% to 80%. Moreover, the molasses showed an additional 20% enhancement of gluconic acid by A.niger in the absence of glucose. The molasses outstanding performance at the end of the bioreactor stage showed a competitive and possible alternative to glucose at the industrial level.