Mutations induced in Pichia kudriavzevii hybrids and tolerance to physical-chemical stress on their growth, production of ethanol and volatile compounds

Abstract

Genetic improvement has become a promising alternative, allowing, for example, the hybridization between species and the induction of genetic mutations in selected strains, aiming to obtain microorganisms with optimized characteristics. Considering these possibilities, in this study, genetic improvement of non-Saccharomyces yeast strains analogous to hybrids was carried out through the application of techniques for random mutation induction. The proposed methodologies consisted of the use of ultraviolet (UV) light and ethidium bromide (EtBr). The mutants obtained from post-hybridization Pichia kudriavzevii were tested for their ability to consume glucose and fructose in sequential fermentation with commercial yeast in sugarcane broth, as well as for ethanol and temperature tolerance and the physicochemical characteristics of the fermented products. The results showed improved performance of the mutants in the evaluated parameters, with increased sugar consumption and enhanced thermal and alcohol tolerance, varying among the samples from the two groups obtained in the mutation induction process (UV-induced mutants: SP 11 UV, SP 24 UV, and SP 27 UV; and ethidium bromide-induced mutants: SP 11 EtBr, SP 24 EtBr, and SP 27 EtBr), making them promising alternatives for application in fermentation processes. Additional tests will be conducted to expand the evaluation of other conditions and biochemical parameters.