Ethanol Production from Whey by Kluyveromyces marxianus in Batch Fermentation System: Kinetics Parameters Estimation

Abstract

Whey is the liquid remaining after milk has been curdled and strained. It is a by-product of the manufacture of cheese or casein and has several commercial uses. In environmental point of view, whey is kind of waste which has high pollution level due to it's contain high organic compound with BOD and COD value 50 and 80 g/L respectively. On the other side, whey also contain an amount of lactose (4.5%-5%); lactose can be used as carbon source and raw material for producing ethanol via fermentation using yeast strain Kluyveromyces marxianus. The objective of this research is to investigate the kinetics of ethanol production from crude whey through fermentation using Kluyveromyces marxianus and to estimate the kinetics parameter using available model. The yeast was able to metabolize most of the lactose within 16 h to give 8.64 g/L ethanol, 4.43 g/L biomass, and remain the 3.122 g/L residual lactose. From the results presented it also can be concluded that common kinetic model for microbial growth, substrate consumption, and product formation is a good alternative to describe an experimental batch fermentation of Kluyveromyces marxianus grown on a medium composed of whey. The model was found to be capable of reflecting all batch culture phases to a certain degree of accuracy, giving the parameter value: µmax, Ks, YX/S, α, β : 0.32, 10.52, 0.095, 1.52, and 0.11 respectively.

Matrices (re)loaded: Durability, viability, and fermentative capacity of yeast encapsulated in beads of different composition during long‐term fed‐batch culture

“…Relative to planktonic yeast grown in chemostats or planktonic yeast in exponential or stationary phase, continuously fed encapsulated yeast exhibits increased transcript levels of genes involved in cell wall remodeling, glycolysis, and stress resistance, and diminished transcript levels of tricarboxylic acid cycle genes and those regulating the cell cycle. At present, because continuous culture systems do not easily scale up, repeated fed-batch culture is the favored means by which yeast is used to produce bioethanol [43][44][45] and other valuable commodities. 42 Encapsulated cells have been studied in both continuous and repeated fed-batch culture systems.…”

Uptake of iron by Kluyveromyces marxianus DSM 5422 cultivated in a whey‐based medium

“…For example, the K S values of K. marxianus for glucose were found to be 0.065 g/L and 0.23 g/L . In contrast, the published K S values of K. marxianus for lactose extend over a wide range: 0.012 g/L , 1.2 g/L , 10.5 g/L , 16 g/L , 20 g/L ; most of these K S values are implausibly high, which could be explained by the unsuitable mode of determination (the adaptation of the model to the measured data via multiparameter variation). Here, the γ μ ( C S,L ) term does not describe the precise μ – C S,L relation, but acts as a trigger from full growth with sugar to no growth after sugar depletion.…”

The Effect of Kluyveromyces Lactis Starter Concentration and Fermentation Time to the Physicochemical and Functional Properties of Egg White Powder

“…The result is supported by Buckle et al (2007) which stated that the loss of CO2 from the egg white would increase the pH value. Ariyanti and Hadiyanto (2013) added that the Kluyeromyces yeast would utilize sugar into ethanol and biomass. The effect of K. lactis starter concentration and fermentation time on egg white powder yield The K. lactis starter concentration combined with fermentation time did not give a significant effect to the egg white powder yield.…”

“…The statistical analysis of water content in egg white powder did not show any significant differences, which is in line with the result of yield measurement as well. However, Ariyanti and Hadiyanto (2013) described that the obtained yields in fermentation products could be increased by the biomass production of bacteria. In their research on Kluyeveromyces yeast fermentation, the yields would be increased as much as 4.5 g/L after 22 h of fermentation.…”