Abstract: The present invention is aimed to provide a method for industrially producing a useful substance (protein etc.) utilizing a bacterium such as Escherichia coli in the presence of a surfactant and a surfactant to be used in this method for producing a useful substance. The present invention is a method for producing a useful substance into a culture solution by secretion by a bacterium in the culture solution, wherein the culture solution contains a surfactant (A), and a dried cell density based on the volume of the culture solution is 1.5 to 500 g/L. More preferably, the present invention is a method for producing a useful substance wherein the surfactant (A) is at least one agent selected from the group consisting of an amphoteric surfactant, an anionic surfactant, and a nonionic surfactant having an HLB value of 0 to 13.

Abstract: The present invention is aimed to provide a method for industrially producing a useful substance (protein etc.) utilizing a bacterium such as Escherichia coli in the presence of a surfactant and a surfactant to be used in this method for producing a useful substance. The present invention is a method for producing a useful substance into a culture solution by secretion by a bacterium in the culture solution, wherein the culture solution contains a surfactant (A), and a dried cell density based on the volume of the culture solution is 1.5 to 500 g/L. More preferably, the present invention is a method for producing a useful substance wherein the surfactant (A) is at least one agent selected from the group consisting of an amphoteric surfactant, an anionic surfactant, and a nonionic surfactant having an HLB value of 0 to 13.

Abstract: The present invention is a bacteriolytic agent containing a cationic surfactant (A) of which a counteranion is an acid having a pKa (25° C.) of 0 to 10. As the counterion, a carboxylate anion is preferable. As the cationic surfactant (A), a quaternary ammonium salt-type surfactant is preferable. Examples of the useful substance include a protein, an amino acid, a nucleic acid, an antibiotic, sugars or vitamins. The bacteriolytic agent of the present invention is excellent in a bacteriolytic power in a step of extracting a useful substance from a microorganism (useful substance producing bacterium etc.). In addition, denaturation of the useful substance during the step is small.

Abstract: A refolding agent and refolding method which make it possible to produce high-purity proteins in high productivity. The refolding agent includes a phosphorus-containing compound (A) and an oxycarbonyl group-containing compound (B). The refolding method includes the step of treating the unfolded protein with the refolding agent. As the compound (A), there may be mentioned at least one species selected from inorganic phosphoric acids, alkyl phosphate esters, sugar phosphate esters, and salts of these, and as the compound (B), there may be mentioned at least one species selected from formic acid, acetic acid, propionic acid, lactic acid, tartaric acid, and salts of these.

Abstract: To provide a surfactant which is obtainable by using substantially no alkali metal, has excellent readhesion prevention ability of finely-pulverized particles at the time of cleaning, and is capable of quite efficient and advanced cleaning. In the present invention, a surfactant which comprises a neutralized salt (AB1) and/or neutralized salt (AB2) is used. Neutralized salt (AB1): a neutralized salt (AB1) which comprises an acidic compound (A1) containing at least each one of an acid group (X1) of an acid having the difference of heat of formation in an acid dissociation reaction (Q1) of 3 to 200 kcal/mol and a hydrophobic group (Y) containing 1 to 36 carbon atoms, and a nitrogen-containing basic compound (B) having the difference of heat of formation in a proton addition reaction of 10 to 152 kcal/mol, wherein (X1) is at least one species selected from a sulfonic acid group, and the like.

Abstract: The present invention is a bacteriolytic agent containing a cationic surfactant (A) of which a counteranion is an acid having a pKa (25° C.) of 0 to 10. As the counterion, a carboxylate anion is preferable. As the cationic surfactant (A), a quaternary ammonium salt-type surfactant is preferable. Examples of the useful substance include a protein, an amino acid, a nucleic acid, an antibiotic, sugars or vitamins. The bacteriolytic agent of the present invention is excellent in a bacteriolytic power in a step of extracting a useful substance from a microorganism (useful substance producing bacterium etc.). In addition, denaturation of the useful substance during the step is small.

Abstract: A refolding agent and refolding method which make it possible to produce high-purity proteins in high productivity. The refolding agent includes a phosphorus-containing compound (A) and an oxycarbonyl group-containing compound (B). The refolding method includes the step of treating the unfolded protein with the refolding agent. As the compound (A), there may be mentioned at least one species selected from inorganic phosphoric acids, alkyl phosphate esters, sugar phosphate esters, and salts of these, and as the compound (B), there may be mentioned at least one species selected from formic acid, acetic acid, propionic acid, lactic acid, tartaric acid, and salts of these.

Abstract: To provide a surfactant which is obtainable by using substantially no alkali metal, has excellent readhesion prevention ability of finely-pulverized particles at the time of cleaning, and is capable of quite efficient and advanced cleaning. In the present invention, a surfactant which comprises a neutralized salt (AB1) and/or neutralized salt (AB2) is used. Neutralized salt (AB1): a neutralized salt (AB1) which comprises an acidic compound (A1) containing at least each one of an acid group (X1) of an acid having the difference of heat of formation in an acid dissociation reaction (Q1) of 3 to 200 kcal/mol and a hydrophobic group (Y) containing 1 to 36 carbon atoms, and a nitrogen-containing basic compound (B) having the difference of heat of formation in a proton addition reaction of 10 to 152 kcal/mol, wherein (X1) is at least one species selected from a sulfonic acid group, and the like.