Trifluorolactate experienced modification of its enantiomeric excess by fractional distillation. Quantitative studies have shown that the separation of an enantiomorph and its racemate is due to a change in boiling points that depend on the enantiomeric excess of the compound. Such a change in the boiling point was not seen in the case of the non fluorinated lactate.

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Rhodococcus rhodochrous PA-34 isolated from soil as a propionitrile-utilizing microorganism, hydrolysed several a-aminonitriles to optically active amino acids. The hydrolysis of a-aminonitriles was found to be catalysed by a nitrilase. The characteristics of the purified enzyme revealed that this is a new nitrilase as it has a molecular mass of 45 k D a and acts as a monomer. The optimum p H and temperature for the activity of the purified enzyme were 7.5 and 35 ° C, respectively. Thiol-specific reagents caused inhibition whereas chelators did not significantly alter the activity of this enzyme. The amino acids produced were of Lform, except for alanine. In the case of leucine production from a-aminoisocapronitrile, the enantiomeric ratio of L-leucine to D-leucine was about 60.

Rhodococcus corallinus (formerly Nocardia corallina) 6-276, isolated with propene as sole carbon and energy source, is able to oxidize trichloroethene (TCE). Glucose-or propene-grown R. corallinus B-276 cells exhibited no difference in TCE degradation efficiency. TCE degradation was found to be growth-phase-dependent and maximum rates were monitored with stationaryphase cells. K,,, and V,,, values for TCE degradation of R. corallinus 6-276 grown in nutrient broth medium in the presence of glucose were 187 pM and 2-4 nmol min" (mg protein)", respectively. fscherichia coli recombinants harbouring and expressing the alkene monooxygenase genes of R. corallinus B-276 exhibited the ability to degrade TCE. This result provides clear evidence that the alkene monooxygenase of R. corallinus B-276 catalyses TCE oxidation. R. corallinus B-276 was shown to contain four linear plasmids, pNCIO (70 kb), pNC20 (85 kb), pNC30 (185 kb) and pNC4O (235 kb). The observation that pNC30-deficient strains had lost the ability to grow on propene suggested that the genes of the propene degradation pathway are encoded by the linear plasmid pNC30. Southern blot analysis with cloned alkene monooxygenase genes from R. corallinus B-276 revealed a positive hybridization signal with the linear plasmid pNC30. This result clearly shows that the alkene monooxygenase is encoded by the linear plasmid pNC30. Eleven short-chainalkene-oxidizing strains were screened for the presence of linear plasmids. Among these, four propene-oxidizing Rhodococcus strains and one etheneoxidizing Mycobacterium strain were found to contain linear megaplasmids. Southern blot analysis with the alkene monooxygenase revealed positive signals with linear plasmids of two propene-oxidizing Rhodococcus ruber strains. These results indicate that homologous alkene monooxygenases are encoded by linear plasmids in R. ruber strains.

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