Related Experiment Video
Updated: Jun 28, 2026

Biogas Purification through the use of a Microalgae-Bacterial System in Semi-Industrial High Rate Algal Ponds
Published on: March 22, 2024
Decrease in hydrogen sulfide content during the final stage of beer fermentation due to involvement of yeast and not
Kaneo Oka1, Teruhiko Hayashi, Nobuya Matsumoto
1Research Center, Suntory Limited, 1-1-1 Wakayamadai, Shimamoto-cho, Mishima-gun, Osaka 618-8503, Japan.
Abstract:
We observed a rapid decrease in hydrogen sulfide content in the final stage of beer fermentation that was attributed to yeast and not to the purging of carbon dioxide (CO(2)) gas. The well known immature off-flavor in beer due to hydrogen sulfide (H(2)S) behavior during beer fermentation was closely investigated. The H(2)S decrease occurred during the final stage of fermentation when the CO(2)-evolution rate was extremely small and there was a decrease in the availability of fermentable sugars, suggesting that the exhaustion of fermentable sugars triggered the decrease in H(2)S. An H(2)S-balance analysis suggested that the H(2)S decrease might have been caused due to sulfide uptake by yeast. Further investigation showed that the time necessary for H(2)S to decrease below the sensory threshold was related to the number of suspended yeast cells. This supported the hypothesis that yeast cells contributed to the rapid decrease in H(2)S during the final stage of beer fermentation.
Related Concept Videos
Microbes in Beverage Production
Microbial Fermentation
Fermentation
Fermentation is a type of metabolic process that occurs in the absence of oxygen, where organic molecules such as glucose are broken down to produce energy. During this process, the...
Production of Alcohol
Fates of Pyruvate
In aerobic organisms, pyruvate is metabolized via the citric acid cycle to produce reduced coenzymes NADH and FADH2. These coenzymes are then oxidized in the electron transport chain to produce ATP and, in the process, regenerate the NAD+ and FAD. As seen in some cell types and organisms, fermentation...
Bioreactor Controls-III

