Date of Award:


Document Type:


Degree Name:

Master of Science (MS)


Nutrition, Dietetics, and Food Sciences


C. A. Ernstrom


Two methods of single-stage fermentation were used to produce methane from whey. The first method involved batch fermentation in which the pH was automatically controlled at 7.0. In addition to pH control, the second method was characterized by introducing the substrate continuously into the fermenter along with dilution water to keep the organic acids at a non-toxic level.

The first method did not improve the production of methane compared to the batch fermentation in which a pH control system was not used (41). However, the second method showed that the concentration of organic acids has a major effect on limiting the production of methane from whey, and that by diluting the substrate with water the concentration of these acids was kept at levels not toxic to methanogenic bacteria until the population of methanogenic bacteria was such that they could convert organic acids to methane as rapidly as the acids were produced by non-methanogenic bacteria in a continuous process. This continuous process was capable of producing .179 m3 methane per kilogram of lactose in cheese whey.