The production of butyrate is used to regenerate the NADP used in conversion of glucose to pentoses and to regenerate the NAD used in the Embden-Meyerhof pathway into which pentose sugars were funnelled.
The production of acetate serves as a pathway for ATP generation.
Hydrogenases also act as a mechanism to regenerate NAD from NADH. In this process hydrogen is produced.
The fermentation of hexoses and pentoses by Butyrivibrio is represented in the following four pictures:
1. the overall pathway showing the breakdown of hexoses and pentoses via Pyruvate and acetyl CoA to produce butyrate and acetate
2. The next image shows the involvement of ferredoxin linked hydrogenases in the catabolism of the sugars to yield acetyl CoA.
3. The next graphic shows acetate production from acetyl CoA with ATP generation and synthesis of acetoacetyl CoA from acetyl CoA
4.The next image shows regeneration of NADP using acetoacetyl CoA, yielding butyrate as a final reduced end product which is released into the growth medium.