Protein production from brewer's spent grain via wet fractionation: process optimization and techno-economic analysis.

Brewer's spent grain (BSG) is the major byproduct generated by the brewing industry. It has 50-70% fiber and 14-30% protein contents. This study investigates the technical and economic performances for producing protein-rich product (PP) from BSG using enzyme-assisted fractionation process. This was done through process optimization, scale-up verification, and techno-economic analysis (TEA). The experiment was conducted with varying enzyme (Alcalase) loadings and enzymatic hydrolysis times. The results showed that the optimal condition was using Alcalase loading of 5 µL/g with hydrolysis time of 1 h for achieving a high protein concentration (46%) in PP and protein separation efficiency (80%). Using the optimal condition, the scaled-up process resulted in a consistent PP composition and protein separation efficiency. The experimental conditions and results were input into process simulation model for determining the mass and energy flows, from which TEA is derived. For a processing plant with a capacity of 590 t wet BSG per day, the minimum selling price of PP (MSPP) to achieve a 5% return was determined to be 1044 USD/t. Sensitivity analysis revealed that Alcalase and BSG costs have the most effect on the MSPP. Besides, protein separation efficiency is an important processing parameter in determining the MSPP. [ABSTRACT FROM AUTHOR]