Interspecies hydrogen transfer and production of acetate in methane suppressed fermentation

• Research unit: COST
• Project number: C96.0057

Key words (English)

Interspecies hydrogen transfer; production of acetate; methane suppressed fermentation; acetate deicers; Clostridium thermolacticum; Moorella thermoautotrophica

Research programs (English)

COST-Action 818 - Hydrogenas and biological redox events in environmental research and biotechnology

Short description (English)

See abstract

Partners and International Organizations (English)

A, B, CH, CZ, D, DK, E, GR, H, I, NL, P, PL, S, SK, UK

Abstract (English)

The ultimate goal of this long-term research is to develop low-cost acetate deicers from cheap feedstocks, such as agro-food industrial wastes. The aim of the present research project was to investigate the feasibility of an anaerobic thermophilic fermentation process using lactose present in milk permeate for acetate production. As such a thermophilic process has never been studied before, no literature review was available. Therefore, the first specific milestone was to screen many different anaerobic thermophilic bacterial strains to select the best-available species for acetic acid production from lactose in pure or mixed culture. Two bacterial strains were found to be appropriate for such a purpose, when grown in free-cell co-culture: Clostridium thermolacticum and Moorella thermoautotrophica. Then, milk permeate was used as feedstock to produce acetate using the co-culture immobilized in a fibrous-bed bioreactor with a minimal nutrient supplementation. About 0.96 gram of acetic acid was produced from each gram of lactose consumed in the co-culture fermentation, nearly the maximum theoretical yield. These promising results indicate that commercial production of acetate from milk permeate should be feasible, since large amounts of milk permeate are available as by-product of cheese industry. Further experiments with a fibrous-bed bioreactor are required in order to improve the productivity by increasing the cell density and using a continuously acetic acid extractive fermentation to avoid a product accumulation, leading to the inhibition of the fermentation process. To unravel biochemical mechanisms controlling the metabolic changes according to growth phases and cultivation conditions should be also an exciting task from a scientific point of view.

References in databases (English)

Swiss Database: COST-DB of the State Secretariat for Education and Research Hallwylstrasse 4 CH-3003 Berne, Switzerland Tel. [phone] Swiss Project-Number: C96.0057