K. marxianus var. lactis was grown in different whey media (sweet, acid and salted (5%) whey) and permeate and tested for optimum incubation period (24-120 hr) for biomass production. The effect of adding either yoghurt starter or L.helviticus (at 2% rate) was also investigated. The optimum pH (3,4,5,6&7), type of supplement to enhance biomass production and the ability of the growth in salted why (0, 3, 5, 7, & 9%) in the presence of lactic acid bacteria was also studied.
The best biomass production by K.marxianus var. lactis was in sweet whey at incubation period of 96 hr in the presence of L.helviticus (2%) and yeast extract (0.2%) at pH 4 to 5. It also caused a high reduction in lactose content and BOD of whey. The biomass production decreased as the salt concentration increased, but in the presence of L.helviticus salt tolerance increased and biomass production increased by 14-35% in the presence of up to 9% salt.