Biological hydrogen production by mixed culture using sugarcane bagasse as substrate

Abstract

This project aims at the production of hydrogen, a clean fuel alternative to fossil fuels and whose combustion produces mainly water. This gas will be produced by fermentation of carbohydrates. It is known that the biological production of hydrogen (biohydrogen) is competitive only if the sources of carbohydrates are inexpensive, as in the case of agroindustrial wastes. Considering that the State of São Paulo is the largest Brazilian sugarcane processor and that this activity generates a large amount of waste rich in carbohydrates, especially sugarcane bagasse, the latter will be studied as substrate for biohydrogen production. However, the carbohydrate contained in this waste should be available for implementation of biohydrogen production. In this project, therefore, an optimization of the hydrolysis of sugarcane bagasse will be carried out on the basis of particle size, acid concentration, temperature and time of treatment, using an experimental design. A mixed culture; i.e., sludge from anaerobic wastewater treatment, subjected to different pretreatments for enrichment with hydrogen-producing bacteria, will be used as inoculum. The conditions suitable for hydrogen production by fermentation, such as initial substrate / microorganism (So / Xo) ratio and temperature (35 and 50 ° C), using sugarcane bagasse as carbon source, will be investigated in anaerobic batch tests. The operation of bioreactors for long time periods, based on conditions set out in batch tests, will provide information about the possibility of stable biohydrogen production from this substrate. In addition, the microbiota present in the batch tests and bioreactors will be monitored using DNA-based molecular tool. These analyses will give evaluation of the genetic variability of the microorganisms involved in fermentation, over the period of production under different conditions of temperature and organic loading rates. (AU)