Growth of the obligate methylotroph Methylobacillus flagellatum under stationary and nonstationary conditions during continuous cultivation.

The growth characteristics of a chemostat culture of the obligate methylotrophic bacterium Methylobacillus flagellatum have been determined. Steady-state cultures growing at a rate of 0.73-0.74 h(-1), equal to the maximal growth rate, were obtained under oxyturbidostat cultivation conditions. The response of a chemostat culture to a pulse increase of methanol concentration was studied. It was shown that slow and rapidly growing cultures of M. flagellatum responded differently to pulse methanol addition. The growth characteristics of slow-growing cultures decreased after methanol addition compared to those of stationary chemostat cultures. The growth characteristics of rapidly growing cultures were practically unchanged with and without pulse methanol addition.

Growth and enzymological characteristics of a pink-pigmented facultative methylotroph Methylobacterium sp. MB1.

Growth characteristics of batch and continuous cultures of the pink facultative methylotroph Methylobacterium sp. MB1 were determined. The response of a chemostat culture to a pulse increase of methanol concentration was studied. Malate, succinate and oxaloacetate additions to the methanol-supplemented medium decreased batch culture growth inhibition by methanol. The carotenoid content in cells grown in a chemostat decreased with increasing growth rate. The key enzyme activities of C1-metabolism were measured in a chemostat culture at different dilution rates.

[The effect of synthetic proteinase inhibitors of the level of human recombinant proinsulin production, secreted by a genetically engineered strain of Bacillus subtilis]. / Vliianie sinteticheskikh ingibitorov proteinaz na uroven' produktsii rekombinantnogo proinsulina cheloveka, sekretiruemogo genno- inzhenernym shtammom Bacillus subtilis.

Influence of O,O,-diethyl-1-(N-alpha-hydrohexafluoroisobutyryl)amino-1- methylpropylphosphonate and O,O-diisobutyl-1-[2-(ethoxycarbonyl)aminoperfluoroprop-2-yl] -1- methylpropylphosphonate on the level of production of human proinsulin secreted by a genetically engineered culture Bacillus subtilis AJ 73 (pBINS1.0.) has been studied. The above phosphonates, being non-toxic for microorganisms, reduced degradation of proinsulin by serine proteinases.

[Growth characteristics of haploid and diploid Hansenula polymorpha yeasts on methanol in continuous culture]. / Kharakteristika rosta gaploidnykh i diploidnykh drozhzhei Hansenula polymorpha na metanole v usloviiakh nepreryvnogo kul'tivirovaniia.

The rate of growth and the yield of biomass of a Hunsenula polymorpha homozygous diploid strain ML-3 X ML-3 were nearly identical with those of the parent haploid culture ML-3. The two cultures were eliminated from the fermenter at D = 0.20 to 0.21 h-1. In contrast, a heterozygous diploid strain ML-3 X VKM 1397 could grow at D = 0.23 to 0.25 h-1 and its biomass yield reached 38% while the yields of the haploid and homozygous diploid strains were 35 to 36%. The pH of the medium had the same effect on the three cultures: a change in the pH from 4.0 to 3.5 and then to 3.0 did not influence the yield of biomass; a further pH drop to 2.5 made the cells be eliminated from the fermenter.

Purification and properties of serine protease from Halobacterium halobium.

Pure extracellular serine protease was isolated from the culture filtrate of Halobacterium halobium by bacitracin-Sepharose affinity chromatography. The enzyme activity was completely and irreversibly lost if the NaCl concentration fell below 2 M. The protease consists of one polypeptide chain with a molecular weight of 41,000. It is characteristically enriched in Asx and Glx content, whereas the level of basic amino acids in the enzyme molecule is unusually low. The protease shows a preference for leucine in the carboxylic side of the scissile bond of the substrate, cleaving the B-chain of oxidized bovine insulin only at the Leu15-Tyr16 bond and liberating p-nitroaniline from L-pyroglutamyl-L-alanyl-L-alanyl-L-leucine-p-nitroanilide.

[Continuous cultivation of Hansenula polymorpha and Candida krusei on mixtures of methyl and ethyl alcohols]. / Nepreryvnoe kul'tivirovanie Hansenula polymorpha i Candida krusei na smesi metilovogo i étilovogo spirtov.

The object of this work was to study whether it would be possible to cultivate together ther the methanol-assimilating yeast Hansenula polymorpha M-2 requiring biotin and thiamine for its growth and the vitamin-prototrophic yeast Candida krusei E-10 actively growing in a medium with ethanol, without vitamin addition to the medium. The growth of the mixed culture in a medium containing ethanol and methanol depended on the pH of the medium; the biomass yield was maximal at pH 3.5 which was the suboptimal value for H. polymorpha M-2. The biomass yield decreased when the relative content of methanol in the mixed substrate was increased. At the optimal pH 3.5 and the optimal methanol-to-ethanol ratio (1:1), the productivity exceeded 2.0 g/litre per hour and the dilution rate D reached 0.17 h-1, the maximal value for H. polymorpha M-2 at this pH. The cultural broth obtained upon the growth of C. krusei E-10 on ethanol as a pure culture could not be used for the cultivation of H. polymorpha M-2 on methanol unless the vitamins were added.