(602j) Effects of Aeration Rate on the Growth Kinetics and Lactate Production of Kluyveromyces Lactis in the Pilot-Scale Bioreactor

Kluyveromyces lactis is viewed as fascinating yeast which has become the studies for decades of its distinctiveness.Based on its status as Generally Regarded As Safe (GRAS) according to Food and Drug Association (FDA), K. lactis has become a potential source of single-cell protein with putative probiotic characteristics as well as oligonucleotide-derived flavor enhancers and lactic acid production. The main goal of the present study is to maximize the cell mass production and lowering the lactate accumulation. This is strategically done using different aeration rate of batch cultivation in 16-L pilot scale stirred tank bioreactor for 48 hours cultivation  with industrial grade of lactose as carbon source. Different aeration rate of 0.5, 1.0 and 2.0 v v^-1 min^-1 gave different concentration of cell mass that were 12.15, 18.6 and 20.35 g L^-1, respectively with increased of lactate concentration concomitanlty with the growth of K. lactis. Lactate was produced in the range of 1.0-1.3 g L^-1 when K. lactis was cultivated under 0.5 v v^-1 min^-1 of aeration rate. Growth of K. lactis under 1.0 v v^-1 min^-1 responded highest lactate production (1.5 g L^-1) with 0.28 g L^-1 hr ^-1 growth rate  and  specific growth rate of 0.13 hr^-1. The highest cell concentration was obtained in a bioreactor for 2.0 v v^-1 min^-1 aeration rate with growth rate of 0.64 g L^-1 hr^-1. Whereby the production of lactate is about 1.08 g L^-1 which was the lowest when compared with other aeration rate. Even the aeration rate of 2.0 v v^-1min^-1 gave the highest cell mass calculated, the growth rate as well as the specific growth rate was the least among three rates examined. This gave the   specific growth rate and doubling timeof 0.1 hr^-1 and 6.94 hr, respectively. The increment of cell mass obtained was only 9.40 %  if  compared with the growth at aeration rate of  1.0 v v^-1min^-1. It is then to be concluded that aeration rate at 1.0 v v^-1min^-1 was the best rate to be further optimized for high cell mass production of K. lactis.