Influence of the cellulose and sulfate ratio on voltage generation in winogradsky columns

Abstract

The Winogradsky column is a nutrient-enriched sediment column for studying microbial diversity and the sulfur cycle. In this device, microorganisms generate a vertical chemical gradient, and voltage production can be measured with a graphite plate (buried in sediment) and a graphite plate (submerged in water). This system is similar to sediment microbial fuel cells (SMFC) used for generating electrical energy. Voltage generation in SMFCs has been established with different cellulose concentrations. However, cellulose and sulfate proportions have not been tested so far. Cellulose/sulfate ratios can change the microbial community, vertical chemical gradient, and potential difference. Therefore, this work aims to test the effect of different cellulose/sulfate ratios in Winogradsky columns to improve voltage generation. Voltage was generated in cellulose/sulfate ratios between 0.08 and 1.28. An optimal cellulose/sulfate ratio of 0.75, identified with the response surface model, produced a voltage between 300 to 400 mV for 20 days. These devices represent an alternative for renewable energy generation where cellulose waste could be used as a carbon source.