Scale-up of a Novel Protein Extraction Process

AgResearch Limited in conjunction with industry partner, Keratec Limited, have been developing a commercially viable protein extraction process. This extraction process results in the generation of several protein-rich streams of varying composition, functionality, and commercial value. This work has focused on the purification and concentration of an acid soluble protein stream in the laboratory, followed by transfer to the full scale, commercial operation. Previous experience has shown that the acid soluble protein stream is sensitive to harsh processing conditions, such as high/low pH and temperature. This can result in a darkening of the colour of the final protein solution and the formation of a cloudy precipitate/haze over time. Laboratory trials identified a range of optimal processing conditions (pH, temperature, pressure, time etc). Pilot scale trials focused on developing a commercially viable production process based on the processing conditions identified in the laboratory. Full scale trials were used to confirm the conditions identified at pilot scale were achievable and commercially viable. This work has identified that membrane filtration, using ultra-filtration (UF) membranes, is an effective method to purify and concentrate the acid soluble protein stream as it reduces the salt content of the fraction containing the larger protein molecules. The final protein yield was optimised by controlling the processing conditions to minimise the leakage through the membrane. The maximum yield was achieved using a two-stage process, combining UF and evaporation, although careful control of the processing conditions (temperature and time) was required to avoid adversely affecting the quality of the final product.