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Abstract: Water miscible metal working fluids (MWF) are prone to contamination by bacteria and fungi. In the present work it was investigated which components of a model MWF emulsion were most readily degraded by microorganisms and which are relatively resistant to biodegradation. The microbial community colonising an MWF emulsion, during its lifetime under in-use conditions was analysed up to species level. Shifts in the composition of microbial community were related to chemical changes in the MWF emulsion over time. [Copyright &y& Elsevier]

The guts of termites feature suitable conditions for methane oxidizing bacteria (MOB) with their permanent production of CH 4 and constant supply of O 2 via tracheae. In this study, we have isolated MOB from the gut contents of the termites Incisitermes marginipennis , Mastotermes darwiniensis , and Neotermes castaneus for the first time. The existence of MOB was indicated by detecting pmoA , the gene for the particulate methane monooxygenase, in the DNA of gut contents. Fluorescence in situ hybridization and quantitative real-time polymerase chain reaction supported those findings. The MOB cell titer was determined to be 10 2 –10 3 per gut. Analyses of the 16S rDNA from isolates indicated close similarity to the genus Methylocystis . After various physiological tests and fingerprinting methods, no exact match to a known species was obtained, indicating the isolation of new MOB species. However, MALDI-TOF MS analyses revealed a close relationship to Methylocystis bryophila and Methylocystis parvus . [ABSTRACT FROM AUTHOR]