[Kinetics of the degradation of aliphatic hydrocarbons by the bacteria Rhodococcus ruber and Rhodococcus erythropolis].

Consumption of aliphatic hydrocarbons by the bacteria Rhodococcus ruber Ac-1513-D and Rhodococcus erythropolis Ac-1514-D grown on mixed n-alkanes and diesel fuel was studied. Consumption of diesel fuel hydrocarbons by the strains was less intense in comparison with the n-alkane mixture. The strains showed differences in growth rate and consumption of the substrates, which suggests that they possess different mechanisms of hydrocarbon uptake.

[Field-scale study on performance comparison of bio-augmentation and compost treatment of oily sludge].

In order to explore better treatment process of oily sludge, the field scale experiments were conducted using the sludge containing 12.68% oil. The performance of microbe preparation bio-augmentation (MPB) and compost treatment with manure (CTM) was compared. For the first experiment, 10 L solution containing 150 g microbe preparations and the nutrition were sprayed onto the MPBC cell. The initial oil content of final mixture amounted to 12.12%. The initial oil content of CTM after final mixture approximated to 10.14%. During the experimental period, same quantities of the microbe preparation and nutrient solution were sprayed on MPB at the 15th and 30th day separately. At the same days, the 10 kg manure was added to CTM cell. The degradation effect of MPB was more obvious, oil content dropped to 6.42% with a 47% removal rate of oil. The oil content in control decreased slightly to 10.15% after 56 days, while in CTM it fell down to 6.98% with a total removal rate of 31%. The pH in control fluctuated slightly between 8.28 to 7.93 while that in MPB, from 7.33 to 8.08, which might due to the addition of microbe preparation. The microbial count was analyzed weekly, which represented the adaptation ability of microbe in sludge. Temperature of compost increased rapidly up to 54 degrees C in the presence of manure. The differences of two kinds of methods were identified by GC-MS and the hydrocarbons with less 21 carbons were degraded easily.

Bioremediation of oil polluted aquatic systems and soils with novel preparation 'Rhoder'.

This paper summarises the experience accumulated during the field application of biopreparation 'Rhoder' (solely or in a combination with preliminary mechanical collection of free oil) for remediation of oil polluted aquatic systems and soils in the Moscow region and Western Siberia during 1994-1999. It was demonstrated that 'Rhoder' had a very high efficiency (>99%) for bioremediation of the open aquatic surfaces (100 m2 bay of the River Chernaya, two 5,000 m2 lakes in Vyngayakha) at initial level of oil pollution of 0.4-19.1 g/l. During remediation of the wetland (2,000 m2) in Urai (initial level of oil pollution of 10.5 g/l), a preliminary mechanical collection of oil was applied (75% removal) followed by a triple treatment with 'Rhoder'. It resulted in an overall treatment efficiency of 94%. Relatively inferior results of bioremediation of the 10,000 m2 wetland in Vyngayakha (65% removal) and the 1,000 m2 marshy peat soil in Nizhnevartovsk (19% removal) can be attributed to the very high initial level of oil pollution (24.3 g/l and >750 g/g dry matter, respectively) aggravated by the fact that it was impossible to apply a preliminary mechanical collection of oil on these sites. A possible strategy for remediation of such heavily polluted sites is discussed.

[Regulation of alpha-amylase biosynthesis in Bacillus diastaticus mutants with various levels of enzyme synthesis]. / Reguliatsiia biosinteza alpha-amilazy u mutantov Bacillus diastaticus s raznym urovnem sinteza fermenta.

The regulation of alpha-amylase biosynthesis was studied in Bacillus diastaticus mutants with different levels of the enzyme synthesis (by two orders of magnitude). The enzyme biosynthesis was shown to be regulated by induction and catabolite repression. Maltose, starch and methyl-alpha,D-glucoside (which cannot be metabolised) induced the synthesis while glucose and fructose acted as catabolite repressors.

[Nucleotide composition and the level of DNA homology in a number of Bacillus diasticus strains]. / Nukleotidnyi sostav i uroven' gomologii DNK riada shtammov Bacillus diastcus.

The base composition of DNA and DNA homology of a number of strains Bacillus diastaticus differing in the intensity of the amilase synthesis and some phenotipic properties have been studied. The differences in the base composition of DNA have not been found. All stains studied are characterized by the high rate of DNA homology. B. diastaticus and B. stearothermophilus have been established to be genetically similar.

[Natural variability of Bacillus diastaticus, a thermophilic bacterium that forms amylase]. / Estestvennaia izmenchivost' termofil'noi bakterii Bacillus diastaticus, obrazuiushchei amilazu.

Natural variability of the thermophilic culture of Bacillus diastaticus was studied, and the population of its cells was found to be genetically heterogeneous. The bulk (75.5%) of the cells had a high activity of amylase biosynthesis; 21.5% of the cells had a low activity; 2.94% of the cells had no activity. One inactive variant and two variants whose activity was higher that that of the parent culture with respect to amylase biosynthesis have been selected.