Abstract
Biodiesel is a reliable option to decrease the consumption of fossil fuels and mitigate its impact on the environment. Biodiesel production generates large quantities of glycerol. Several attempts are being made to find a proper use for this new waste, including methane fermentation. Acclimation of sludge from a food factory to produce methane from glycerol was carried out. Anaerobic sequencing batch reactor (ASBR) with 3L of working volume was used. Seeding material was 300ml of sludge. Temperature was 39°C and agitation 100rpm. Daily, 750mL of liquid medium was withdrawn, 750mL of medium with glycerol as the only carbon source was added (HRT of 4 days) and the pH was adjusted to 7.6. The organic loading rate was 2.5gCOD/l/d. Methane and VFAs production was monitored. Samples of granule were taken periodically and DGGE analysis was conducted. The sequences of different bands were determined to identify the main bacteria and archaea communities. An important change in the microbial community occurred. Some of the identified microorganisms hasn´t been reported in the methane fermentation of glycerol. The aim of the present study was to elucidate the shifts of bacterial and archaeal communities over time in the acclimation to glycerol of repeated-batch methane fermentation.
