Biodegradation of petroleum sludge and petroleum polluted soil by a bacterial consortium: a laboratory study.

This article presents a study of the efficiency and degradation pattern of samples of petroleum sludge and polluted sandy soil from an oil refinery. A bacterial consortium, consisting of strains from the genera Pseudomonas, Achromobacter, Bacillus and Micromonospora, was isolated from a petroleum sludge sample and characterized. The addition of nitrogen and phosphorus nutrients and a chemical surfactant to both the samples and bioaugmentation to the soil sample were applied under laboratory conditions. The extent of biodegradation was monitored by the gravimetric method and analysis of the residual oil by gas chromatography. Over a 12-week experiment, the achieved degree of TPH (total petroleum hydrocarbon) degradation amounted to 82-88% in the petroleum sludge and 86-91% in the polluted soil. Gas chromatography-mass spectrometry was utilized to determine the biodegradability and degradation rates of n-alkanes, isoprenoids, steranes, diasteranes and terpanes. Complete degradation of the n-alkanes and isoprenoids fractions occurred in both the samples. In addition, the intensities of the peaks corresponding to tricyclic terpenes and homohopanes were decreased, while significant changes were also observed in the distribution of diasteranes and steranes.

Inhibition of fungal sphingolipid biosynthesis by rustmicin, galbonolide B and their new 21-hydroxy analogs.

The mode of action of the known antifungal macrolides rustmicin (1) and galbonolide B (2) has been determined to be the inhibition of sphingolipid biosynthesis. A large scale fermentation and isolation process was developed for production of large quantities of rustmicin. New 21-hydroxy derivatives of both compounds were isolated from pilot scale fermentations and were also produced by biotransformation of rustmicin and galbonolide B.

Inhibition of DNA topoisomerases by microbial inhibitors.

New inhibitors of DNA topoisomerase named 2280-DTI and 2890-DTI have been discovered in the culture filtrates of Micromonospora sp. strain No. 2280 and Streptomyces sp. strain No. 2890, respectively. Both inhibitors were purified from each culture filtrate by column chromatography on Diaion, Dowex and gel filtration. Both inhibitors were thermostable acidic substances with high molecular weight and inhibited topoisomerase I in a non-competitive manner. They differed from well-known inhibitors of topoisomerases such as camptothecin and doxorubicin, which inhibit the DNA rejoining reaction of the enzyme by intercalation into DNA strands or stabilizing the cleavable complex (enzyme-DNA reaction intermediate). 2280-DTI and 2890-DTI did not intercalate into DNA strands and also had no ability to stabilize the cleavable complex. It is suggested that 2280-DTI and 2890-DTI inhibit the DNA breaking and rejoining reactions of topoisomerase by direct action on the enzyme molecule.

[Dependence of the component makeup of the gentamicin complex on Micromonospora purpurea var. violacea 1935 cultivation conditions]. / Zavisimost' komponentnogo sostava gentamitsinovogo kompleksa ot uslovii kul'tivirovaniia Micromonospora purpurea var. violacea 1935.

Dependence of biosynthesis of gentamicin and vitamin B12 on complex and "synthetic" media under conditions of decreased aeration, increased phosphorus levels and non-optimal content of carbon source was studied. The decreased levels of vitamin B12 production under conditions of the non-optimal content of the carbon source and increased phosphorus levels in the medium resulted in decreased production of the antibiotic complex as a whole and decreased relative content of the most methylated gentamicins C1 and C2 in the complex. Decreased aeration lowered the mycelium productivity with respect to the antibiotic production without changing the ratio of the components in the complex and the level of vitamin B12 production.

[Effect of cobalt on the growth of a Micromonospora purpurea var. violacea 1935 culture and on the biosynthesis of gentamincin]. / Vliianie kobal'ta na rost kul'tury Micromonospora purpurea var. violacea 1935 i biosintez gentamitsina

The effect of cobalt on growth of Micromonospora purpurea var. violacea 1935 and biosynthess of gentamicin in complex soy-bean meal or "synthetic" gelatin medium was studied. In optimal concentrations cobalt increased the activity level of the culture fluid almost 6 times in both media having practically no effect on the amount of the mycelium formed. Addition of cobalt to the medium resulted in retardation of the organism growth and consumption of the nutrients. Stimulation of gentamicin biosynthesis by cobalt was inversely proportional to the time of the trace element addition. The cobalt effect depended on the aeration conditions, inorganic phosphorus level in the medium and physiological condition of the mycelium.

Formation of methylated and phosphorylated metabolites during the fermentation process of verdamicin.

In an attempt to understand the biosynthetic processes leading to the formation of verdamicin (end product), we have examined the patterns of the formation of methylated and phosphorylated metabolites, which resulted from either the addition of l-[methyl-(14)C]methionine or [(32)P]KH(2)PO(4) to the fermentation. Incorporation of label from l-[methyl-(14)C]methionine into the bioactive sisomicin, verdamicin, and the chromatographically polar components increased with the progression of time. Two methylated bioinactive metabolites were found in the culture broth after removal of the methylated bioactive metabolites. In contrast to the bioactive metabolites, incorporation of the methyl-(14)C label into the two methylated bioinactive metabolites decreased with the progression of time. A phosphorylated bioinactive metabolite (nonmethylated) was also found in the culture broth, fermented in the presence of [(32)P]KH(2)PO(4). The role of the phosphorylated metabolite in the biosynthesis of the bioactive metabolites cannot yet be explained.