Analysis of the methane production in thermophilic anaerobic reactors: use of autofluorescence microscopy

Abstract

Methanogenic activity in thermophilic, anaerobic reactors was determined by comparing the amount of methane generated in single- and two-stage systems with the size of the methanogenic population, as determined by microscopy. The methanogenic activities were 2.71 × 10−9 ml methane cell−1 d−1 and 1.10 × 10−9 ml methane cell−1 d−1 for 10 and 4 days of the hydraulic retention time (HRT), in the single-stage system. In the two-stage system, 7.49 × 10−9 ml methane cell−1 d−1 in the acidogenic reactor and 1.56 × 10−9 ml methane cell−1 d−1 in the methanogenic reactor for 4 days of the HRT. A high correlation was evident between the methane production and methanogenic population [0.1354 ln(x) − 2.1375](R 2 0.8619).