Evaluating biochemical methane production from brewer's spent yeast.

Abstract

Anaerobic digestion treatment of brewer's spent yeast (SY) is a viable option for bioenergy capture. The biochemical methane potential (BMP) assay was performed with three different samples (SY1, SY2, and SY3) and SY1 dilutions (75, 50, and 25% on a v/v basis). Gompertz-equation parameters denoted slow degradability of SY1 with methane production rates of 14.59-4.63mL/day and lag phases of 10.72-19.7days. Performance and kinetic parameters were obtained with the Gompertz equation and the first-order hydrolysis model with SY2 and SY3 diluted 25% and SY1 50%. A SY2 25% gave a 17% of TCOD conversion to methane as well as shorter lag phase (<1day). Average estimated hydrolysis constant for SY was 0.0141 (±0.003) day(-1), and SY2 25% was more appropriate for faster methane production. Methane capture and biogas composition were dependent upon the SY source, and co-digestion (or dilution) can be advantageous.