A factorial design was used to determine the main effects and interactions of pH (3.6, 3.8 and 4.0), SO2 (25 and 50 mg/l), ethanol (7%, 10% and 13%, v/v) and temperature (15°C and 25°C) on the growth of 54 Leuconostoc oenos strains. These differed greatly in their ability to survive adverse conditions. Under the test conditions, temperature had a profound effect on growth. The power pH values of 3.6 and 3.8 had a marked inhibitory effect on growth, as did at the lower temperature of 15°C. The higher concentrations of SO2 (50 mg/l) and ethanol (13%) had the greatest inhibitory effect on growth, and with a synergistic effect when both SO2 and ethanol were added to the test medium. Based on these results, five strains were selected that were best capable of surviving the adverse conditions studied. These strains will be used for further study on the induction of malolactic fermentation in wine.

Phenotypic data of 108 tests conducted on 70 malolactic bacteria, including 54 presumptive Leuconostoc oenos strains, five presumptive pediococci isolated from wine and 11 reference strains, were analysed by numerical taxonomic techniques. Using the simple matching coefficient, 58 strains were grouped in six clusters at the 87% S level. Cell wall analysis of the interpeptide bridges and morphology was also used to differentiate between the strains. No L. oenos reference strains were found to group in any cluster. The hypothetical median organism (HMO) of cluster A was related at only the 63% S level to the L. oenos type strain and it is proposed that these strains be regarded as ‘L. gracile’. The majority of the L. oenos strains (35) grouped together at above the 91% S level in cluster B, with the HMO of this cluster related at the 75% S level to the L. oenos type strain. Results indicate that the majority of L. oenos strains included in this study are closely related, but more research is needed to justify the separation of these strains into more than one species.

Eighty‐four nocardioform bacteria freshly isolated from soil samples have been compared with 28 marker cultures in a numerical taxonomic study in which 114 unit characters were determined. The strains were recovered in seven major clusters and two minor clusters. Nine strains could not be assigned to any one of the clusters. Six of the major clusters could be identified with named cultures or type strains of Rhodococcus erythropolis, R. rubropertinctus, and R. terrae, R. equi, R. rhodocrous, R. coprophilus and Mycobacterium fortuitum. Three of the local isolates were recovered in a minor cluster related to the M. fortuitum cluster. Three type strains and two marker cultures of the genus Nocardia were grouped in a minor cluster. The remaining major cluster consisted of 16 strains that were identified as rhodococcal strains. However, these 16 strains could not be equated with any of the established Rhodococcus species. It is therefore proposed that these strains be considered a new species within the genus Rhodococcus for which the specific name Rhodococcus australis is proposed. A description of the new species is given.

Five lactic acid bacteria capable of carrying out the malolactic fermentation were studied at 15°C and 25°C. Results indicated that at 15°C hardly any glucose, fructose and l‐malic acid was utilized over a 9d period. After 9d at 25°C very little glucose and fructose and most (if not all) of the l‐malic acid was degraded. The addition of ethanol markedly affected the l‐malic acid utilization by the four Leuconostoc oenos strains at 25°C. Large differences in their ability to convert l‐malic acid were found amongst the four strains in media containing 5% and 10%(v/v) ethanol.

The cellular fatty acid composition of 70 lactic acid bacteria was examined by capillary gas chromatography. Fifty‐four Leuconostoc oenos strains, including three reference, type strains from the other Leuconostoc spp., nine Pediococcus spp. and two Lactobacillus spp. were studied. Eighteen fatty acids were determined, of which 10 were identified by gas chromatography‐mass spectrometry. The relative percentages of the 18 fatty acids of the Leuconostoc strains were analyzed numerically and grouped using the unweighted pair‐group method. Results show that four clusters could be defined at r= 0.920, with five strains unassigned. The major fatty acids of the Leuc. oenos strains were found to be palmitic acid (C16:0), palmitoleic acid (C16:1–9), oleic acid (C18: 1–9), vaccenic acid (C18: 1–11), dihyrosterculic acid (C19‐cyclopropane‐9) and lactobacillic acid (C19‐cyclopropane‐11). It was mainly on the basis of the amounts of oleic acid and the C19‐cyclopropane fatty acids that the strains of Leuc. oenos could be distinguished from each other. This is the first report of the occurrence of dihydrosterculic acid in lactic acid bacteria. For the majority of Leuc. oenos strains, the result obtained with the cellular fatty acid analysis confirmed the phenotypic relationships.