A novel, oil-degrading bacterium (strain T1) was isolated from a hot spring in Hokkaido, Japan. It efficiently degrades different types of fats and oils, including edible oil waste. When grown in a mineral salt medium containing 1% triacylglycerol (as salad oil), hydrolysis products were 1,3- and 1,2-diacylglycerols, monoacylglycerol, and free fatty acid. However, these products were almost completely consumed during cultivation at 30 degrees C for 5 days, indicating that extracellular lipase acts randomly at different sn-positions of acylglycerols and that strain T1 has a high capacity to utilize free fatty acids. Secreted lipase activity was induced by salad oil and oleic acid. This strain was a Gram-negative straight rod shaped, aerobic, with a polar flagellum, capable of growing in temperature ranges between 15 degrees C and 55 degrees C. The 16S rRNA gene sequence analysis and DNA-DNA hybridization revealed it as a new strain of Pseudomonas aeruginosa. The type strain was T1.

The alkane (pristane) degradation capacity o f Rhodococcus erythropolis PR4 (NBRC 100887), isolated from marine environment, was previously observed. In this study, the ability of this strain for biodegradation of various animal fats, such as pig lards and poultry fats as well as butter, margarine and sunflower cooking oil was studied. Bioconversion of fats and oil was determined as methyl-ester (FAME) derivatives by GC-MS. R. erythropolis PR4 strain could utilize all substrates tested but the bioconversion rate and efficacies varied. The optimum pH for decomposition of pig lard and poultry fat was 8.5, respectively. Addition of carbonate to the media dramatically improved the efficiency o f the process via stabilization of pH o f the fermentation. Biotransformation of poultry fat was complete in four days and around 80% conversion was reached in the case of pig lard in media containing carbonate. The extracellular lipase activity of the R. erythropolis PR4 strain was also demonstrated by various techniques. The results suggest the R. erythropolis PR4 strain studied is a promising candidate in bioremediation/bioconversion of fatcontaining wastes within a relatively short time.

Petroleum hydrocarbons and derivatives are widespread contaminants in both aquifers and soil, their elimination is in the primary focus of environmental studies. Microorganisms are key components in biological removal of pollutants. Strains capable to utilize hydrocarbons usually appear at the contaminated sites, but their metabolic activities are often restricted by the lack of nutrients and/or they can only utilize one or two components of a mixture. We isolated a novel Rhodococcus sp. MK1 strain capable to degrade the components of diesel oil simultaneously. The draft genome of the strain was determined and besides the chromosome, the presence of one plasmid could be revealed. Numerous routes for oxidation of aliphatic and aromatic compounds were identified. The strain was tested in ex situ applications aiming to compare alternative solutions for microbial degradation of hydrocarbons. The results of bioaugmentation and biostimulation experiments clearly demonstrated that - in certain cases - the indigenous microbial community could be exploited for bioremediation of oil-contaminated soils. Biostimulation seems to be efficient for removal of aged contaminations at lower concentration range, whereas bioaugmentation is necessary for the treatment of freshly and highly polluted sites.