Effect of glucose concentration on the rate of fructose consumption in native strains isolated from the fermentation of Agave duranguensis

Abstract

Studies on hexose consumption by Saccharomyces cerevisiae show that glucose is consumed faster than fructose when both are present (9:1 fructose to glucose) in the medium during the fermentation of Agave. The objective of this work was to select strains of S. cerevisiae that consume fructose equal to or faster than glucose at high fructose concentrations by analyzing the influence of different glucose concentrations on the fructose consumption rate. The optimal growth conditions were determined by a kinetics assay using high performance liquid chromatography (HPLC) using 50 g of glucose and 50 g of fructose per liter of synthetic medium containing peptone and yeast extract. Using the same substrate concentrations, strain ITD-00185 was shown to have a higher reaction rate for fructose over glucose. At 75 g of fructose and 25 g of glucose per liter, strain ITD-00185 had a productivity of 1.02 gL(-1) h(-1) after 40 h and a fructose rate constant of 0.071 h(-1). It was observed that glucose concentration positively influences fructose consumption when present in a 3:1 ratio of fructose to glucose. Therefore, adapted strains at high fructose concentrations could be used as an alternative to traditional fermentation processes.

Respiro-fermentative metabolism in yeast cultivated in solid-state culture: The Crabtree effect and ethanol production

“…The yeasts employed in this paper were commercial baker's yeast, Saccharomyces cerevisiae ITD00196 (Díaz-Campillo et al, 2012), Scheffersomyces stipitis ATCC58785, Scheffersomyces stipitis Y-17104, Kluyveromyces marxianus CBS6556, and Schwanniomyces occidentalis ATCC26077. The inoculum production assays were carried out with conventional, coiled, and baffled 250 mL Erlenmeyer flasks (Pyrex, Borosilicate glass, USA), as reported by Marín-Palacio et al (2014).…”

“…The agitation in the bioreactor could help the homogenization of the SSM and improve the speed of the process. The yeast S. cerevisiae ITD00196 was selected because it has been characterized for ethanol production (Díaz-Campillo et al, 2012). The possibility of producing ethanol with a pilot batch bioreactor using 25 kg WM of the SSM without any thermochemical or enzymatic pre-treatment was demonstrated, however, differences were found that could be diminished with better control of the process, using, for example, a thermal pretreatment (Estrada-Martínez et al, 2019).…”