[Purification and properties of two enzymes of meta-cleaving the aromatic ring controlled by the biphenyl biodegradation plasmid pBS 241 from Pseudomonas putida]. / Ochistka i svoistva dvukh fermentov meta-rasshchepleniia aromaticheskogo kol'tsa, kontroliruemykh plazmidoi biodegradatsii bifenila pBS 241, iz bakterii Pseudomonas putida]

It was shown that two metapyrocatechases (EC 1.13.11.2) function in Pseudomonas putida BS893. Biphenyl degradative plasmid pBS241 carries the genes of these enzymes. The basic properties of the both enzymes, i. e., MPC1 and MPC2, were investigated. It was found that MPC1 is an enzyme with a molecular mass of 135 kD and has a heterotetrameric subunit structure (alpha 2 beta 2), being made up of two non-identical polypeptides with Mr of 34 and 22.5 kD; pI is 5.15, the pH optimum is at 8.0, a temperature optimum is at 54 degrees C. MPC2 has a molecular mass of 154 kD and possesses a homotetrameric subunit structure (alpha 4); it consists of identical polypeptides with Mr of 41 kD and has a pI of 4.95, a pH optimum at 7.5 and a temperature optimum at 60 degrees C. The substrate specificity of the enzymes was studied, and the Km and Vmax values for substituted catechols were determined. MPC1 shows a high affinity for 2.3-dihydroxybiphenyl and hydrolyzes 3-methylcatechol and catechol (but not 4-methylcatechol) at a low rate. MPC2 has a moderate affinity for catechol, 3- and 4-methylcatechols, but is incapable of cleaving 2.3-dihydroxybiphenyl. Both enzymes share in common some typical properties of metapyrocatechases. The different role of MPC1 and MPC2 in biphenyl catabolism is discussed.

[Plasmid participation in the degradation of alpha-methylstyrene]. / Uchastie plazmid v degradatsii al'fa-metilstirola.

Pseudomonas acidovorans 9 transforming alpha-methylstyrene into acetophenone contains four types of plasmid DNA with molecular masses of 130, 110, 36 and 54 MD. The loss of the "growth on alpha-methylstyrene" property by this strain correlates with the absence of plasmids with the molecular masses of 130 and 110 MD from the cells. All the types of plasmid DNA are found in transconjugants growing on alpha-methylstyrene and produced by crossing the parent P. acidovorans strain with the plasmidless variant of this strain incapable of alpha-methylstyrene transformation. Apparently, plasmids with the molecular masses of 130 and 110 MD participate in the genetic control of alpha-methylstyrene transformation into acetophenone by P. acidovorans 9.

[A strain of Pseudomonas aeruginosa growing on petroleum hydrocarbons]. / Shtamm Pseudomonas aeruginosa, rastushchii na uglevodorodakh nefti.

The strain Pseudomonas aeruginosa BS313 was used to isolate mutants that are capable to utilize octane as the sole carbon source. By means of conjugation plasmids of camphor (CAM) and naphthalene (pBS2) biodegradation were inserted into one of the mutant strains P. aeruginosa BS316. The resultant strain P. aeruginosa BS315 shows the capacity to degrade aliphatic, aromatic and cyclic oil hydrocarbons.

[Naphthalene oxidation by a Pseudomonas putida strain carrying a mutant plasmid]. / Okislenie naftalina shtammom Pseduomonas putida, nesushchim mutantnuiu plazmidu.

Naphthalene oxidation by a parent and a mutant strain of Pseudomonas putida was studied. The parent strain contained a plasmid NPL-1 which controlled oxidation of naphthalene to salicylic acid and was capable of oxidizing salicylate. The mutant strain did not oxidize salicylate because of a mutation in salicylate hydroxylase; it contained also a mutant plasmid NPL-41 which determined constitutive synthesis of naphthalene oxygenase. Salicylic acid which accumulated as a product of naphthalene catabolism in the cultural broth of the wild strain was found to undergo further oxidation by the population of growing cells. The content of salicylic acid in the cultural broth of the mutant strain reached maximum and then remained constant. An anion-exchange resin was tested in order to prevent the inhibition of naphthalene oxygenase by salicylate and to increase the yield of salicylic acid. The transmissible character of the mutant plasmid NPL-41 makes it possible, with the aid of conjugation, to construct Pseudomonas strains which would oxidize naphthalene to salicylic acid without further degradation of this compound.

[Microbiological transformation of carbohydrates. Glucose isomerization into fructose by washed cells of Streptomyces sp. strain 29]. / Mikrobiologicheskaia transformatsiia uglevodov. Izomerizatsiia gliukozy vo fruktozu otmytymi kletkami Streptomyces sp. shtamm 29.

Glucose-fructose transformation by washed and packed cells of Streptomyces sp. 29 was studied. The cells grown on the nutrient medium containing xylose and Co and Mg salts were capable to perform glucose-fructose isomerization. The cellular activity depended in a great degree on the temperature, pH and initial glucose concentration; to a lesser extent on Co and Mg ions present in the incubation mixture, and did not depend on the age of the culture (within 8-69 hours). The activity reached its maximum at 70-80 degrees C, pH 7.0 and a low concentration of glucose (10(-3) M). Under these conditions the yield of fructose was 50% from the initial glucose concentration (or 100% from the theoretical value). Washed cells of Streptomyces sp. 29 packed into a thermally controlled column continuously transformed glucose to fructose during 24 days with a yield of 30-44%.