Abstract: Provided is a production method for a soluble material, including: causing a solid raw material containing at least one component of a hydrolyzable material selected from the group consisting of a protein, a carbohydrate and a lipid, and a fibrous material, and water in an amount corresponding to 0.04 to 2.4 parts by weight with respect to 1 part by weight of a dry amount of the raw material to coexist; applying a shearing force in a state where heating and pressurization are performed at 200 to 374° C. and in a pressure range equal to or higher than a vapor-liquid coexistence curve of water to hydrolyze at least a part of the hydrolyzable material and/or to amorphize at least a part of the fibrous material; and halting the pressurization to cause adiabatic expansion.

Abstract: A method for purifying an amino acid selected from the group consisting of valine, leucine and isoleucine easily in high yield and with high purity using an inexpensive precipitant, comprising allowing p-ethylbenzenesulfonic acid or its water-soluble salt to act on an aqueous solution containing an amino acid to form crystals of the amino acid p-ethylbenzenesulfonate and then separating and decomposing the crystals to purify and obtain the amino acid. The p-ethylbenzenesulfonic acid may be used as the free acid, an alkali metal salt and an ammonium salt.

Abstract: A process for recovering a high-purity L-amino acid from a fermentation liquor obtained by fermentation or an enzymic method, which comprises removing the impurities contained in said fermentation liquor by passing said fermentation liquor through an ultrafilter membrane and then through an ion-exchange or adsorbent resin; concentrating or cooling the effluent thus obtained to result in crystallization of said L-amino acid, and isolating said crystalline L-amino acid from said fermentation liquor.

Abstract: A process for recovering a high-purity L-amino acid from a fermentation liquor obtained by fermentation or an enzymic method, which comprises removing the impurities contained in said fermentation liquor by passing said fermentation liquor through an ultrafilter membrane and then through an ion-exchange or adsorbent resin; concentrating or cooling the effluent thus obtained to result in crystallization of said L-amino acid, and isolation said crystalline L-amino acid from said fermentation liquor.