Development of protein extraction from agricultural waste as potential growth stimulator

Abstract

Soybean waste obtained during processing of soy products was found to be rich in protein and adequate in supporting the growth of microorganisms such as fungus Rhizopus oligosporus. The objective of this study was to optimize a process for extracting proteins from soybean waste and develop the protein extract as growth stimulator. The extraction process involved homogenizing the soybean waste in phosphate buffer solution with NaCl to dissolve and maximize the proteins solubility and centrifuging the water soluble fraction. In order to improve the protein extraction yield, the optimum pH buffer and the solid-to-liquid ratio were determined through optimization using response surface methodology. The results proved that the protein extraction step was effective and successfully enhanced the protein extraction yield. Two steps design of experiments were carried out and the best conditions for maximizing protein extraction yield were found to be homogenizing with phosphate buffer of pH 7 and solid-to-liquid ratio of 7 %w/v. The optimized protein extract was used to develop the agar culture medium along with glucose monohydrate which showed significant growth of fungus Rhizopus oligosporus and Phanerochaete chrysosporium indicating the soybean waste’s protein extract was a potential growth stimulator.