( ( ( A ( ( more subtle ) consumption ) ) ( of oxygen ) ) ( ( occurs ( ( ( ( during ( bacterial action ) ) , ) as ) ( in ( the ( fermentation process ) ) ) ) ) . ) )
(ROOT (S (NP (NP (DT A) (ADJP (RBR more) (JJ subtle)) (NN consumption)) (PP (IN of) (NP (NN oxygen)))) (VP (VBZ occurs) (PP (PP (IN during) (NP (JJ bacterial) (NN action))) (, ,) (RB as) (PP (IN in) (NP (DT the) (NN fermentation) (NN process))))) (. .)))
A more subtle consumption of oxygen occurs during bacterial action, as in the fermentation process.
(ROOT (S (NP (NNP Fermentation)) (VP (VBZ is) (NP (NP (DT the) (NN process)) (PP (IN of) (S (VP (VBG making) (NP (NN atp)) (PP (IN without) (NP (NN oxygen)))))))) (. .)))