Effect of glucose level on the batch production of β-1,3-glucanase by Trichoderma harzianum and cell growth

Abstract

The effect of initial glucose concentration on β-1, 3-glucanase production by Trichoderma harzianum NCIM 1185 and cell growth was studied in a batch stirred tank bioreactor. The initial glucose level was varied between 5 g/dm³ and 100 g/dm³. A maximum β-1,3-glucanase production of 0.820 U was obtained using the fully optimized medium which had an initial glucose level of 8.63 g/dm³ and thereafter there was a steady decrease in β-1,3-glucanase production. No β-1,3-glucanase production was observed beyond initial glucose concentrations of 40 g/dm³ which suggests a possible catabolic repression on the enzyme synthesis. The inhibitory effect of increased initial glucose concentrations on cell growth has been studied and the Luong and the Han-Levenspiel models were used to explain the mechanism of inhibition.