초록
Acidification of wheat bread (WBS), rye bread (RBS) and fresh biowaste suspensions (FBS), leading to lactate+acetate, lactate+acetate+n-buyrate, and acetate+propionate+n-butyrate, respectively, and biogas production as well as population dynamics were investigated. Co-fermentation of FBS (14kgm<SUP>-3</SUP>d<SUP>-1</SUP> organic loading rate (OLR)) with WBS or RBS was stable up to an OLR of 22kgm<SUP>-3</SUP>d<SUP>-1</SUP> and resulted in up to 3 times as much biogas. During co-fermentation at more than 20kgm<SUP>-3</SUP>d<SUP>-1</SUP> OLR the total population increased more than 2-fold, but the originally low share of propionate-oxidizing bacteria significantly decreased. The proportion of methanogens also decreased. Whereas the proportion of Methanosarcinales to Methanomicrobiales in biowaste and biowaste+WBS remained constant, Methanosarcinales and in particular Methanosaeta spec. in the biowaste+RBS assay almost completely disappeared. Methanomicrobiales increased instead, indicating propionate oxidation via acetate cleavage to CO<SUB>2</SUB> and hydrogen.