RESUMO
OBJECTIVES: Major lignocellulosic inhibitory compounds found in sugarcane-based industrial hydrolysate samples were tested in laboratory and industrial yeast strains, as well as in lactic acid bacteria, in order to verify their effects on important physiological parameters. RESULTS: Saccharomyces cereviaise SA-1, an industrial strain, stood out as compared to the remaining strains for virtually all inhibitors investigated. This strain presented the highest growth rate and the lowest lag-phase in the presence of acetic acid, levulinic acid, p-coumaric acid, ferulic acid, and HMF, when compared to the other strains. In sugarcane-based hydrolysate fermentations, both SA-1 and CEN.PK113-7D presented similar fermentation performances. Industrial isolates of contaminating lactic acid bacteria were evaluated in the presence of an inhibitory cocktail, containing a mixture of 76.6 mM acetic acid, 1.3 mM HMF, 7.1 mM furfural, and 1.9 mM p-coumaric acid. Whilst all yeast strains were unable to grow under such conditions, bacteria had an average inhibition of roughly 50% on their growth rates. CONCLUSIONS: Overall, industrial strain SA-1 might be a promising microbial chassis for second generation ethanol production and for future metabolic and evolutionary engineering strategies, and for strain robustness understanding.
