Table 4.

Average gene copy numbers per mL digester sludge of total bacteria and three syntrophic acetate-oxidizing bacteria species

Digester	Total bacteria	S. schinkii	T. acetatoxydans	C. ultunense
D37	4.6 ± 4.1 × 109	3.0 ± 3.2 × 108	2.1 ± 3.1 × 107	8.2 ± 8.0 × 106
D42	8.8 ± 5.6 × 109	10.0 ± 7.0 × 108	3.0 ± 2.3 × 108	5.5 ± 2.8 × 107
DTE37	6.8 ± 6.2 × 109	7.7 ± 6.2 × 106	0.9 ± 1.0 × 107	6.1 ± 3.4 × 106
DTE42	4.5 ± 3.8 × 109	6.1 ± 1.7 × 107	6.2 ± 4.6 × 107	5.4 ± 2.4 × 107

qPCR analyses were performed in triplicate DNA extractions from samples withdrawn on days 21, 49, 77, 126, 168, 253 and 280 of operation