Production of ethanol from whey permeate
Cheese whey represents an important source of environmental pollution due to its enormous global production rate and high organic matter content. One good method to deal with whey pollution is its bioconversion to ethanol employing yeast, especially Kluyveromyces species. The only fermentable sugar in whey is the disaccharide lactose which means that wild type Saccharomyces yeasts cannot degrade it because they do not have β-galactosidase. Apart from lactose, whey also contains vitamins and minerals which may improve the physiological activity of the cells.
Ethanol has tremendous applications in chemical, pharmaceutical and food industries in the form of raw material, solvent and fuel. The annual production of industrial ethanol is about four million tonnes, 80% of which is produced by fermentation. It is very important to choose a strain with suitable physiological characteristics to achieve a good utilization of lactose from whey.
The main aspect of this project is the formation of ethanol from crude whey with Kluyveromyces marxianus leading to maximum lactose utilization and ethanol. Both commercial strains and strains isolated from Icelandic dairy products will be examined. Experiments are done to maximize ethanol yields by varying various environmental parameters, such as oxygen, stirring, initial substrate concentrations and inocula volume.
Jóhann Örlygsson, Professor, School of Business and Science, University of Akureyri, Iceland
Mjňlkursamslan - MS (Iceland Diaries), Iceland