A study by Osaka Metropolitan University found that persimmon tannin helps the yeast Saccharomyces cerevisiae grow 8.9 times better in ethanol, attributing this to the antioxidative properties of the tannin which reduce stress but do not protect cell membranes.
Antioxidants sourced from natural origins enhance the growth of a yeast strain in the presence of ethanol.
While ethanol in alcoholic drinks can impair motor functions, it can also fuel vehicles in a cleaner, more eco-friendly way. The production of ethanol requires yeast, which, ironically, is stressed by ethanol, affecting its growth. In the pursuit of efficient bioethanol production, researchers are exploring substances that enhance yeast’s resilience to ethanol, though they have identified only a few effective options so far.
An Osaka Metropolitan University research team, including graduate student Ilhamzah and Professor Ken-ichi Fujita of the Graduate School of Science and Professor Akira Ogita of the Research Center for Urban Health and Sports, has found that tannin from persimmons improves the growth of the yeast strain Saccharomyces cerevisiae in the presence of ethanol.
“In this study, yeast cultures grown in a medium containing ethanol and persimmon tannin showed an 8.9-fold increase in cell number compared to cultures grown in an ethanol medium without persimmon tannin,” stated Professor Fujita.
This powder was used to create the supernatant that showed some beneficial antioxidative properties that help yeast grow. Credit: Osaka Metropolitan University
Exploring Persimmon Tannin’s Benefits
The researchers explored persimmon tannin because it is known for its antioxidative properties.
“Persimmon tannin reduced ethanol-induced oxidative stress,” Fujita added. “However, persimmon tannin did not prevent ethanol-induced cell membrane damage. This indicates the potential of persimmon tannin as a protective agent to enhance the yeast’s tolerance to ethanol stress by limiting oxidative damage, rather than limiting damage to the yeast’s cell membranes.”
Reference: “Persimmon tannin promotes the growth of Saccharomyces cerevisiae under ethanol stress” by Ilhamzah, Yuka Tsukuda, Yoshihiro Yamaguchi, Akira Ogita and Ken-ichi Fujita, 6 March 2024, Journal of the Science of Food and Agriculture.
DOI: 10.1002/jsfa.13439
The study was funded by the Japan Society for the Promotion of Science.
“…, it [ethanol] can also fuel vehicles in a cleaner, more eco-friendly way.”
With the caveats that 1) ethanol has a lower energy density, meaning less energy can be stored in a fixed-volume fuel tank; 2) crops used to ferment ethanol compete with growing food and water usage for humans and animals, and 3) more than about 10% ethanol in gasoline creates special problems for the engine components (like seals) that have to be specially designed, which may have unanticipated environmental consequences. If this ‘secret ingredient’ were used to reduce acreage used to grow ethanol feed-stock, then I would say that the environmental impact would be positive. However, I’m concerned that the result would be cheaper ethanol and a push to increase the acreage withdrawn from food production.
I was thinking the same thing myself the other day about the food, that was extremely evil what Obama did about encouraging the use of corn for the production of fuel; the price of corn in Central and South America shot up, so too then did the price of taco shells etc; placing extreme stress on the poor just to stay alive.