Abstract: When industrially separating and purifying poly-3-hydroxyalkanoic acid produced by a microorganism, to obtain poly-3-hydroxyalkanoic acid agglomerates having an arbitrary volume mean particle diameter with favorable productivity and with decreased amount of an organic solvent used is enabled while decreasing contaminants derived from constitutive components of cellular bodies. According to the present invention, agglomerates of poly-3-hydroxyalkanoic acid are obtained by adjusting the pH of an aqueous poly-3-hydroxyalkanoic acid suspension to fall within an acidic region.

Abstract: When industrially separating and purifying poly-3-hydroxyalkanoic acid produced by a microorganism, to obtain poly-3-hydroxyalkanoic acid agglomerates having an arbitrary volume mean particle diameter with favorable productivity and with decreased amount of an organic solvent used is enabled while decreasing contaminants derived from constitutive components of cellular bodies. According to the present invention, agglomerates of poly-3-hydroxyalkanoic acid are obtained by adjusting the pH of an aqueous poly-3-hydroxyalkanoic acid suspension to fall within an acidic region.

Abstract: When industrially separating and purifying poly-3-hydroxyalkanoic acid produced by a microorganism, to obtain poly-3-hydroxyalkanoic acid agglomerates having an arbitrary volume mean particle diameter with favorable productivity and with decreased amount of an organic solvent used is enabled while decreasing contaminants derived from constitutive components of cellular bodies. According to the present invention, agglomerates of poly-3-hydroxyalkanoic acid are obtained by adjusting the pH of an aqueous poly-3-hydroxyalkanoic acid suspension to fall within an acidic region.

Abstract: The present invention has an object to provide a method for separating and purifying a PHA without causing a serious decrease of the molecular weight to obtain a highly pure PHA in a high yield, which comprises efficiently removing cell components other than PHA particles from a cultured PHA-containing microbial cell. Another object of the present invention is to provide a method for obtaining an agglomerate of PHA particles. The method for recovering a PHA according to the present invention is a method which comprises efficiently disrupting a cell to recover the PHA by carrying out a physical disruption treatment and an alkali addition at low temperature for an aqueous suspension of the PHA-containing microbial cell, and then treating the PHA with an enzyme and/or a surfactant. Moreover, the particle diameter of the PHA may be enlarged by suspending the PHA in a hydrophilic solvent and/or water, and stirring at a temperature equal to or below the boiling point of said suspension, to agglomerate said PHA.

Abstract: The present invention has an object to provide a method for separating and purifying a PHA without causing a serious decrease of the molecular weight to obtain a highly pure PHA in a high yield, which comprises efficiently removing cell components other than PHA particles from a cultured PHA-containing microbial cell. Another object of the present invention is to provide a method for obtaining an agglomerate of PHA particles. The method for recovering a PHA according to the present invention is a method which comprises efficiently disrupting a cell to recover the PHA by carrying out a physical disruption treatment and an alkali addition at low temperature for an aqueous suspension of the PHA-containing microbial cell, and then treating the PHA with an enzyme and/or a surfactant. Moreover, the particle diameter of the PHA may be enlarged by suspending the PHA in a hydrophilic solvent and/or water, and stirring at a temperature equal to or below the boiling point of said suspension, to agglomerate said PHA.

Abstract: Ethyl-.beta.-benzoyacrylate is reacted with an alkali metal salt of (S)-alanine or an alkali metal salt of N.sup.6 -trifluoroacetyl-L-lysine to form the corresponding Michael addition product, and not less than an equivalent amount of acid is added after completion of the Michael addition to prevent conversion of the (S,S) form of the product to the (R,S) form.