KCl/KOH supplementation improves acetic acid tolerance and ethanol production in a thermotolerant strain of Kluyveromyces marxianus isolated from henequen (Agave fourcroydes)

Kluyveromyces marxianusis the fastest-growing eukaryote on Earth and a promising non-conventional yeast for different biotechnological applications. One of these applications is production bioethanol from lignocellulosic hydrolysates at high temperature. Here, new thermotolerant strain K. marxianus(Kmx24) was isolated cooked henequen core. Its tolerance to acetic acid, one most common fermentation inhibitors present in hydrolysates, examined. Growth ethanol glucose by Kmx24 were inhibited acid concentrations > 1.5 g/L. This sensitivity alleviated supplementation culture medium with KCl/KOH (40/10 mM) both 30 42oC, although observed effect not so marked 42oC. Increased cell viability wall stiffness addition presence acid. It suggested that improved due an increase potassium uptake allowing efficient proton efflux, increased membrane integrity strengthened electrochemical potential. The link between needs further study. Temperature stress caused decrease which relieved addition.