Non-conventional yeast Meyerozyma guilliermondii strain Y-780 as a protein producer in the submerged fermentation of sawmill waste hydrolysate

The annual generation of wood waste in the Russian Federation is currently estimated at 75–113 million cubic meters. The conversion of these lignocellulosic residues into value-added products, including bioenergy sources, feed additives, and organic acids, constitutes a priority within the nation’s environmental policy framework. This study details the production of a protein-rich product from the biomass of the non-conventional yeast Meyerozyma guilliermondii strain Y-780 cultivated on a hydrolysate derived from sawmill waste. An analysis of the cultivation process revealed that the yeast metabolized the bulk of reducing substances within the first 48 hours, concomitant with a phase of vigorous biomass accumulation. The investigation of the pH influence revealed that the strain Y-780 of Meyerozyma guilliermondii exhibited substantial yeast growth on the hydrolysate at a pH of 4.6. The incorporation of corn extract into the mineral culture medium based on the hydrolysate led to an almost threefold increase in biomass yield compared to media containing only inorganic nitrogen sources. The research established a distinct consumption profile for reducing substances by the yeast, which was highly dependent on the composition of the culture medium. The addition of nitrogen, vitamins, and biogenic elements to the hydrolysate resulted in an enhancement of its nutritional value, leading to an increase in crude protein yield to 47%. These findings suggest the biological suitability of the wood sawdust hydrolysate and underscore the significant biotechnological potential of Meyerozyma guilliermondii strain Y-780 for feed protein biosynthesis.