Changes in microbial community structure in two anaerobic systems to treat bagasse spraying wastewater with and without addition of molasses alcohol wastewater

► Investigation of bacterial community in bioreactors treating wastewater from bagasse spraying with or without added MAW. ► Archaeal community was analyzed by PCR-DGGE and 16S rRNA clone library. ► Shifts in the diversity and abundance were observed in reactors with and without addition of MAW. ► The number of bacteria is reduced by about 34.8% when 15% MAW was added.