The objective of the current study was to determine growth and acid-forming activities, morphology and physiology of Yarrowia lipolytica Wratislawia 1.31. The process was started as a fed-batch cultivation after that repeated batch cultivation was carried out in 4 batches for each volume of changing medium (0.4 and 0.5 dm³). When 0.4 dm³ of fresh medium was exchanged this strain produced 175 g · dm^-3 citric acid and the citric acid yield was high 0.66 g·g^-1. Increasing the volume of medium exchanged (to 0.5 dm³) affected the lower concentration of citric acid to 120 g · dm^-3 but increase the concentration of biomass and erythritol was observed. Physiological state assessment of yeasts used in the study showed their good viability and high genetic and phenotypic stability.

In this work the influence of atmospheric conditions on stability of alginate beads containing immobilized Yarrowia lipolytica yeast cells after their storage in field during five months of autumn-winter was measured. In laboratory, the influence of soil supplementation by yeasts on oats germination and autochthonic soil microflora was analyzed. Autumn-winter storaged beads contained living Y. lipolytica yeasts. Beads presence had a positive effect on autochthonic microflora, causing increase of microbial cells number. In laboratory tests, supplementation of soil by yeasts preparation (suspension or beads) caused amelioration of oats germination and increase in autochthonic microbial cells number. Obtained results clearly encourage to continue the study on formulation of Y. lipolytica yeasts bioproduct, designated to direct soil application.

Simultaneous saccharification and ethanol fermentation of corn starch using enzyme preparation Stargen 001 was investigated. The experiments were conducted in an agro-distillery plant. The preparation of corn mashed based on the use of corn flour suspended in recycled liquid fraction of stillage and distillation condensates. It was shown that the final concentrations of ethanol after fermentation of 25% w/v mashes were of 8–10% w/v. The elimination of cooking for starch liquefaction allowed to reduce of energy requirements, nevertheless, made s serious problem with bacterial contamination of mashes. The concentration of lactic acid at the end of fermentation process reached up to 3.8% w/v. The SFF process connected with repeated stillage recycling allowed to remove water requirements and to perform this process as discard-less.