Biomedical subjects

M Z Zakirov

Publications and source records attributed to M Z Zakirov.

11 recordsLinked to original sources

PubMedDate not supplied

[Rhizopus microsporus strain UzLT-I--a thermotolerant producer of lipase].

The properties of the thermotolerant fungus Rhizopus microsporus strain UzLT-1--producer of lipolyptic enzymes are described. Optimal cultivation conditions--40 degrees, C, pH 4.5--Are determined. The lipolytic activity of the culture on the medium consisting of corn extract (2%), cotton-seed oil (1%) and water is 850 ml 0.1 n KOH per 100 ml culture liquid. The enzymic preparations of lipase have been precipitated by isopropanol and ammonium sulphate. The preparation precipitated by isopropanol shows its macimum activity at pH 4.2 and 7.8 and a temperature of 40--50 degrees C.

Culture Media↗

PubMedDate not supplied

[Oospora lactis strain actively producing lipase].

Morphological, cultural and physiological properties of the fungus Oospora lactis producing lipase are described. The activity of lipase depends on the composition of a growth medium, pH, temperature, the duration of cultivation. Optimum conditions for lipase biosynthesis by the fungus have been found. The strain produces extracellular and endocellular lipases during submerged cultivation in the optimum growth medium at a high rate.

Culture Media↗

PubMedDate not supplied

[Partial purification and properties of protease from Torula thermophila].

11-Fold purified protease preparation is isolated from cultural medium of Torula thermophila UzPT-1 by means of ammonium sulphate precipitation and gel chromatography through Sephadex G-100. Disc polyacrylamide gel electrophoresis revealed two portease components, one of them possessing proteolytic activity. pH interval for protease activity was found to be 3.5-12, the maximal activity was observed at pH 8.5-11, the highest enzyme resistance--at pH 6-8. The enzyme almost completely preserved its activity for 1 hour in distilled water at 60 degrees C. The temperature maximum of the enzyme activity was 70 degrees at pH 8. The enzyme may be referred to proteases of serine nature, because it is completely inactivated with diisopropylphosphofluoridate, but it retains the activity in the presence of chelating agents (EDTA, o-phenantroline, ditizone) and inhibitors of SH-groups (sodium p-chloromercuriumbenzoate, iodoacetic acid). The enzyme was not inactivated with phenylmethylsulphonylfluoride and the trypsin inhibitor from soybean. The protease studied most efficiently hydrolyzed caseine and hemoglobin, in a less degree--human serum albumin and fibrinogen and almost did not attack egg albumin. The enzyme undergoes association-dissociation under pH change during gel filtration through Sephadex.

Chelating Agents↗

PubMedDate not supplied

[Torula thermophila, strain UzPT-1 a thermophilic producer of proteolytic enzymes].

The properties of the thermophilous fungus Torula thermophila producing proteolytic enzymes are described. Oprimal conditions for its cultivation are established. The maximum action of the preparation isolated from the culture liquid filtrate is at pH 9-11. The temperature maximum of the enzyme activity is 70 degrees C.

Cryptococcus↗

PubMedDate not supplied

[Induced variability of the lipase producing fungus Rhizopus microsporus].

The most effective way for inducing mutants of Rhizopus microsporus with an elevated lipolytic activity is the combined action of nitrosomethyl urea and UV. Variants with the lipolytic activity of 3600--3700 units per 1 ml have been produced, thus being by 72--75% more effective than the parent culture.

Dose-Response Relationship, Drug↗

PubMedDate not supplied

[Effect of various procedures of storing the fungus Rhizopus microsporus UzLT-1, a lipase producer].

The effect of various storage procedures on the viability and synthesis of lipolytic enzymes by Rhizopus microsporus UzLT-1 was studied. The best procedures of producer storage proved to be regular passages and lyophilization. These procedures made it possible to maintain stable activity of lipolytic enzymes produced by the fungus for a long time. The fungal storage in vaseline oil or in a dried state was less effective due to significant losses of its lipolytic capacity.

Lipase↗

PubMedDate not supplied

[Effect of cultivation temperature on thermal stability of lipolytic enzymes of the fungus Rhizopus microsporus, UzLT-1].

The yield, activity and thermal stability of lipolytic enzymes obtained from the culture fluid filtrates of Rhizopus microsporus, UzLT-1, cultivated at 28, 38 and 48 degrees C (preparations I, II and III, respectively) were investigated. Maximal lipolytic activity was found in Prepartion II, and maximal yield and thermal stability in Preparation III. By disc electrophoresis and DEAE-cellulose chromatography, the presence of three lipolytically active enzymes in the preparations was demonstrated.

Kinetics↗

PubMedDate not supplied

[Effect of different nitrogen sources on the biosynthesis of lipase by Oospora lactis].

The effect of inorganic and organic nitrogen compounds on the synthesis of biomass and extracellular lipase by Oospora lactis was studied. Among the inorganic nitrogen sources ammonium sulphate and ammonium secondary phosphate and among the organic nitrogen sources yeast autolysate proved to be most beneficial for the lipase synthesis. Lipase activity and biomass accumulation in the medium containing yeast autolysate were greater than in the media containing the above ammonium salts. Lipase synthesis reached maximum in the nutrient medium containing yeast autolysate (0.7%) and ammonium sulphate (0.3%).

Ammonium Sulfate↗

PubMedDate not supplied

[Growth and lipolytic activity of Rhizopus microsporus at various cultivation temperatures].

The dynamics of growth and exolipase biosynthesis was studied in the fungus Rhizopus microsporus under laboratory and semi-industrial conditions at 28, 38 and 48 degrees C. As the temperature rises, the lag-phase as well as the exponential and stationary phases of growth are reduced while the specific growth rate increases. The accumulation of the biomass was found to correlate with the production of the enzyme which was most intensive at the end of exponential growth when the formation of spores was intensive. The greatest lipolytic activity of the cultural broth was recorded at the beginning of stationary growth of the culture. The lipolytic activity hardly changed at the stationary phase of growth and fell down abruptly when the cells died off. The temperature of 38 degrees C was optimal for the accumulation of biomass and lipase in the cultural broth. Good results were obtained at 28 degrees C, but the cultivation was prolonged by 5--7 hours. The yield of the biomass and the level of the lipolytic activity are much lower at 48 degrees C although the specific growth rate is high.

Hydrogen-Ion Concentration↗

PubMedDate not supplied

[Effect of various nitrogen sources on lipase formation by Rhizopus microsporus].

The effect of organic and mineral nitrogen sources on the production of lipolytic enzymes and the accumulation of biomass was studied with Rhizopus microsporus UzLT-I. Addition of mineral nitrogen sources to the growth medium weakly stimulated synthesis of lipase by the fungus. The production of lipolytic enzymes was highest on media with organic nitrogen compounds, particularly yeast autolysate and fodder yeast cells (0.1: 0.25%). The lipolytic activity of the cultural broth on media with these nitrogen sources increased by 50% cf. the control.

Culture Media↗

PubMedDate not supplied

[Effect of metal ions on the lipolytic activity of Rhizopus microsporus].

Various metal ions have different effect on the lipolytic activity of Rhizopus microsporus in the course of cultivation on nutrient media having diverse composition. The fungus particulary requires metal ions for the production of lipase on a mineral medium. Additional introduction of microelements into a medium containing maize extract has no significant effect on the lipolytic activity. Active biosynthesis of lipase by the culture requires zinc.

Enzyme Induction↗