Recovery of volatile fatty acids and enzymes from dilute model aqueous and ruminal waste streams

The enormous volume of rumen fluid from animal processing industries offers a tremendous potential for tapping acetic acid, propionic acid, butyric acid, α-amylase and cellulase. By recovering these compounds, not only is the high COD burden greatly reduced, but also one could expect financial returns by selling the recovered chemicals. A process operation, commensurate with the disposal requirements of the meat processor which isolates the compounds of interest successfully, is essential. The goal of this work is to study the feasibility of recovering useful chemicals such as acetic, propionic, and butyric acids (APBs), along with enzymes like α-amylase and cellulase, either individually or concomitantly from rumen fluid. The make-up of the ruminal solution was first characterized for chemical oxygen demand, and the quantities of chemicals of interest present in it. Various unit operations were studied using creaked mixtures of model dilute aqueous solutions consisting of either acids, or enzymes, or both. The concentrations in the model solutions were chosen to mimic the solute concentrations found in rumen waste. Some of the separation methods studied using the model solutions, which were effective, were then extended to treat actual clarified rumen fluid (supernatant). A methodology to simultaneously recover acids and enzymes from ruminal fluid is proposed. An economical process scheme is developed by combining different unit operations for the recovery of APBs and enzymes