Effect of pH, aeration and sucrose feeding on the invertase activity of intactS. cerevisiae cells grown in sugarcane blackstrap molasses

Abstract

S. cerevisiae was grown in a blackstrap molasses containing medium in batch and fed-batch cultures. The following parameters were varied: pH (from 4.0 to 6.5), dissolved oxygen (DO) (from 0 to 5.0 mg O2 L-1) and sucrose feeding rate. When glucose concentration (S) was higher than 0.5 g L-1 a reduction in the specific invertase activity of intact cells (v) and an oscillatory behavior of v values during fermentation were observed. Both the invertase reduction and the oscillatory behavior of v values could be related to the glucose inhibitory effect on invertase biosynthesis. The best culture conditions for attaining S. cerevisiae cells suitable for invertase production were: temperature = 30 degrees C; pH = 5.0; DO = 3.3 mg O2 L-1; (S) = 0.5 g L-1 and sucrose added into the fermenter according to the equations: (V-Vo) = t2/16 or (V - Vo) = (Vf - Vo).(e0.6t-1)/10.

Effect of cultivation conditions on invertase production by hyperproducing Saccharomyces cerevisiae isolates

“…The final pH of the medium was 6.7. Many workers have reported similar results (Vitolo et al 1995;Herwig et al 2001, Belcarz et al 2002. Higher growth rate was observed at pH 5.5, however maximum product rate was noted at initial pH 6.…”

“…the medium resulting in glucose-induced repression of invertase (Elorza et al 1977;Vitolo et al 1995). At concentrations of sucrose less than 30.0 g/l, enzyme production was less than optimum.…”

Exploitation of for the Heterologous Production of Cellulases and Hemicellulases

“…The production of cost-effective hydrolases requires the use of inexpensive cultivation medium such as molasses based medium. Whereas growth and production of primary metabolites on molasses based industrial medium has been reported in literature [29,30], few studies have considered production of recombinant proteins on such medium. Therefore, we also explored the impact of cultivation conditions and strain properties on growth and production of recombinant Xyn2 -xylanase produced by A. niger D15 in a medium consisting solely of diluted molasses (diluted to 20% molasses in water).…”

Production of Invertase by Aspergillus niger Under Solid State Fermentation Using Orange Fruit Peel as Substrate

“…To determine the optimum pH for Invertase production, pH of the production medium was adjusted [11] (with 0.1 N HCl and 0.1 N NaOH) to different pH values of 3, 4, 5, 6, 7 and then inoculated with 4% inoculum prepared from a 5 day old slant culture and incubated at 30°C for 4 days. The strain has shown maximum Invertase production when the initial pH of the medium was 5 ( Figure 4 and Table 2).…”