The production of hydrogen gas by Chlamydomonas reinhardtii in sulfur-deprived conditions under red light and white light.

Abstract

As we continue to deplete our limited supply of fossil fuels, finding an alternative energy source is becoming a growing concern. Chlamydomonas reinhardtii, a green microalga, utilizes the enzyme hydrogenase to produce hydrogen gas, which has become increasingly considered as a potential fuel source. We conducted a study to determine under what light wavelength conditions C. reinhardtii produces the greatest amount of hydrogen gas. Because oxygen inhibits the activity of hydrogenase, we placed C. reinhardtii in sulfur-deprived medium to induce anaerobic metabolism, thus promoting hydrogen production. We then tested the effects of light wavelength on the hydrogen metabolism of the organism by comparing hydrogen gas produced by cultures under red light versus cultures exposed to white light. Sulfur-deprived and regular media C. reinhardtii cultures were placed under both red and white light separately and a water displacement apparatus was used to measure gaseous volume change due to hydrogen production. Our results demonstrated no statistically significant differences among the treatments exposed to red light and those exposed to white light with regards to hydrogen production, and we therefore failed to reject our null hypothesis. However, we observed trends of sulfur-deprived cultures under red light producing more hydrogen than those under white light. Additionally, existing literature supports these trends in hydrogen production between cultures exposed to different wavelengths of light. Therefore, we discuss that perhaps the discrepancy in our results may be due to the low numbers of replicates utilized and to experimental errors.