The fermentation of lactate and acrylate by the rumen micro-organism lc

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Abstract
Cell-free extracts of the rumen organism LC ferment lactate and acrylate at the same rates to yield H, CO2, acetate and propionate in the same proportions. Dialysis of the extracts for 4-6 hour abolished the fermentation of both substrates but activity was restored by the addition of "sparker" amounts of adenosine tri- or di-phosphate, pyruvate or acetyl phosphate. Further, acrylate "sparked" lactate fermentation and lactate "sparked" acetylate fermentation. Extracts dialysed for 16 hours fermented neither substrate even on addition of "sparkers" but catalysed an oxidation-reduction reaction between lactate and acrylate, yielding pyruvate and propionate as the immediate products. Lactate fermentation by undialysed extracts was completely inhibited by 2 m[image]-arsenate, 100 [mu][image]-hydroxylamine, 20 [mu][image]-2:4-dinitrophenol and 2m[image]-azide. Acrylate fermentation was completely inhibited by 10 mM-arsenate, 20 [mu][image]-hydroxylamine, 10 [mu][image]-2:4-dinitrophenol and 200 [mu][image]-azide. Centrifuging the extracts at 144,000 G for 1 hour did not affect their sensitivity to the inhibitors. The enzymes lactate oxidase and acrylate reductase were demonstrated in crude extracts.