CELL YIELD (Y(M)) OF THAUERA-SELENATIS GROWN ANAEROBICALLY WITH ACETATE PLUS SELENATE OR NITRATE

Thauera selenatis was grown anaerobically in minimal medium with eithe r selenate or nitrate as the terminal electron acceptor and acetate as the carbon source and electron donor. The molar cell protein yields, Y(M)-protein (selenate) and Y(M)-protein (nitrate), were found to be 7 .8 g cell protein/mol selenite formed and 7.5 g cell protein/mol nitri te formed, respectively. These values represent Y(M) values of 57 and 55 g (dry weight)/mol acetate when selenate or nitrate was the electro n acceptor, respectively. Based upon a calculated Y(ATP) value of 10.0 g (dry weight) cells/mol ATP, for growth on acetate in inorganic salt s, growth with selenate as the terminal electron acceptor theoreticall y yielded 5.7 ATP/acetate oxidized, and 5.5 ATP when nitrate was the t erminal electron acceptor. The results support the conclusion that ene rgy is conserved via electron transport phosphorylation when selenate or nitrate reduction are the terminal electron acceptors during anaero bic growth with acetate.