Anaerobic digestion treatment has been one of the effective treatment options for biodegradable organic waste as it effectively reduces the amount of organic waste and produces bio-energy as a renewable energy.

Anaerobic digestion involves a series of metabolic reactions (hydrolysis, acidogenesis, acetogensis and methanogenesis). Among these, intermediate products of anaerobic digestion thus volatile fatty acids (acetic acid and butyric acid etc) are among the most favored for methane formation particularly acetic acid contributes more than 70% to the methane formation. On the other hand, acetic acid, butyric acid, isobutyric acid, isovaleric acid, and propionic acid have been known as good indicators for monitoring performance of anaerobic digestion process, especially in the activity of acetogenic and methanogenic bacteria.

To achieve your goal of producing VFAs without methane/hydrogen production, then you will need to shut down or "kill" the activities of

methanogenic bateria and hydrogen producing bacteria within the microbial communities. also you some hydrogen are also produced

prior to methanogensis therefore, population of the hydrogen consuming bacteria could also be enhanced. To be able to shut down activities

mentioned above, pretreatment of the innoculum used in the anaerobic digestion process needs to be done.

One protocol to help shut down the activities of methanogens include the addition of 2-bromoethanesulfonic acid (BESA) with a concentration of 50 µM into the anaerobic sludge used for the anaerobic digestion.

Herein, methanogens within sludge will be eliminated by BESA to prevent VFAs oxidation during the hydrolysis-acidification step.

This method is one sure way to shut down the activities of methanogens in an AD system.

If you want to produce more VFA, you need to stay fermented in the acidified phase and our results show that it is most efficient to entangle VFA in the case of micro-aerobic.