Millisia

Mil.li'si.a N.L. fem. n. named after Nancy F. Millis, a celebrated microbiologist who promoted wastewater microbiology in AustraliaActinobacteria / Actinobacteria / Corynebacteriales / Nocardiaceae / MillisiaAerobic, Gram‐stain‐positive to Gram‐stain‐variable, acid–alcohol‐fast, nonmotile, catalase‐positive actinomycete that forms non‐sporing rods which show only rudimentary right‐angled branching and which contain polyphosphate storage granules. In stationary phase, the rods fragment into spherical unicells (Figure 1). Salmon pink, irregular colonies with filamentous margins and sparse unbranched aerial hyphae are formed on glucose‐yeast extract agar. Colonies are matt and dry in appearance, soft in texture, and easy to emulsify. Diffusible pigments are not produced. Whole‐organism hydrolysates are rich in meso‐diaminopimelic acid, arabinose, and galactose. The organism contains N‐glycolated muramic acid residues, a predominant dihydrogenated menaquinone with eight isoprene units, and diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol, and phosphatidylinositol mannosides as major polar lipids. Mycolic acids have 44–52 carbon atoms (principal components C48, C50, and C52), and oleic, palmitic, and palmitoleic acids are the predominant fatty acids, with relatively small amounts of myristic, stearic, and tuberculostearic acids. A member of the family Nocardiaceae in the order Corynebacteriales.DNA G+C content (mol%): 64.7 (HPLC).Type species: Millisia brevis Soddell, Stainsby, Eales, Kroppenstedt, Seviour and Goodfellow 2006a, 742VP.<br/

Dispelling the "Nocardia amarae" myth: a phylogenetic and phenotypic study of mycolic acid-containing actinomycetes isolated from activated sludge foam.

Right-angle branched filaments and rods micromanipulated from activated sludge foam and mixed liquor were identified as putatively novel members of the genera Gordonia, Mycobacterium and Rhodococcus using a combination of chemical, molecular and morphological data. Pyrolysis mass spectrometric analyses of gordoniae isolated in both the present and a previous study revealed pyro-groups, distinct from validly described Gordonia species, which could be equated with those based on morphological properties and 16S rDNA data. Putative gordoniae assigned to one of these groups were found to be closely related to strains currently identified as "Rhodococcus australis". These strains were also found to have properties consistent with their classification in the genus Gordonia. The results of this study highlight the limitations of the microscopic approach to filament identification and cast further doubt on the view that foaming can be attributed to members of one or a few Nocardia species

Gordonia defluvii sp. nov., an actinomycete isolated from activated sludge foam.

Three strains of non-motile, Gram-positive, filamentous actinomycetes, isolates J4T, J5 and J59, initially recognized microscopically in activated sludge foam by their distinctive branching patterns, were isolated by micromanipulation. The taxonomic positions of the isolates were determined using a polyphasic approach. Almost-complete 16S rRNA gene sequences of the isolates were aligned with corresponding sequences of representatives of the suborder Corynebacterineae and phylogenetic trees were inferred using three tree-making algorithms. The organisms formed a distinct phyletic line in the Gordonia 16S rRNA gene tree. The three isolates showed 16S rRNA gene sequence similarities within the range 96.9–97.2 % with their nearest phylogenetic neighbours, namely Gordonia bronchialis DSM 43247T and Gordonia terrae DSM 43249T. Strain J4T was shown to have a chemotaxonomic profile typical of the genus Gordonia and was readily distinguished from representatives of the genus on the basis of Curie-point pyrolysis mass spectrometric data. The isolates shared nearly identical phenotypic profiles that distinguished them from representatives of the most closely related Gordonia species. It is evident from the genotypic and phenotypic data that the three isolates belong to a novel Gordonia species. The name proposed for this taxon is Gordonia defluvii sp. nov.; the type strain is J4T (=DSM 44981T=NCIMB 14149T)

Millisia brevis gen. nov., sp. nov., an actinomycete isolated from activated sludge foam.

The taxonomic position of two mycolic-acid-producing actinomycetes, isolates J81T and J82, which were recovered from activated sludge foam, was clarified. Comparative 16S rRNA gene sequence studies indicated that the organisms formed a distinct lineage within the Corynebacterineae 16S rRNA gene tree. The taxonomic integrity of this group was underpinned by a wealth of phenotypic data, notably characteristic rudimentary right-angled branching. In addition, isolate J81T contained the following: meso-diaminopimelic acid, arabinose and galactose; N-glycolated muramic acid residues; a dihydrogenated menaquinone with eight isoprene units as the predominant isoprenologue; a fatty acid profile rich in oleic and palmitoleic acids and with relatively small proportions of myristic, stearic and tuberculostearic acids; mycolic acids with 44–52 carbons; and diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylinositol and phosphatidylinositol mannosides as major polar lipids. Strain J81T was found to have a chemotaxonomic profile that serves to distinguish it from representatives of all of the other taxa classified as belonging to the suborder Corynebacterineae. In the light of these data, it is proposed that the two isolates be classified in a novel monospecific genus. The name proposed for this taxon is Millisia brevis gen. nov., sp. nov.; strain J81T (=DSM 44463T=NRRL B-24424T) is the type strain of Millisia brevis

WASTE TREATMENT: THE FILAMENTOUS BACTERIA CAUSING BULKING AND FOAMING IN ACTIVATED SLUDGE PLANTS

Although the activated sludge system has operated globally to treat both domestic and industrial wastes for more than 80 years, it is still treated very much as a "black box" by the engineers. It is a biological process, and yet until very recently, little understanding of the microbiology of this huge biotechnological industry has been forthcoming. There are good reasons for this, most of which are methodological. Activated sludge is a highly complex ecosystem and, until quite recently, the methods available for identifying and characterising the bacteria there were inadequate, even in the unlikely event that they could be grown in pure culture. The advent of molecular methods to study natural communities of microbes including those found in activated sludge has revolutionised our ideas on their composition. Even so, many engineers (with some justification it has to be said) would claim that the microbiologists have promised much but in reality have contributed little to our understanding of how these plants work, or how their operational efficiencies might be improved. They could argue that all the microbiologist has achieved is to add to the confusion by showing that the microbial communities are far more diverse than were previously thought likely (Amann et al., 1996, 1998; Snaidr et al., 1997; Seviour &amp; Blackall, 1999), but without suggesting how this information might be beneficial to the operators faced with the more mundane daily tasks of running these plants..

Waste treatment: the filamentous bacteria causing bulking and foaming in activated sludge plants

Although the activated sludge system has operated globally to treat both domestic and industrial wastes for more than 80 years, it is still treated very much as a "black box" by the engineers. It is a biological process, and yet until very recently, little understanding of the microbiology of this huge biotechnological industry has been forthcoming. There are good reasons for this, most of which are methodological. Activated sludge is a highly complex ecosystem and, until quite recently, the methods available for identifying and characterising the bacteria there were inadequate, even in the unlikely event that they could be grown in pure culture. The advent of molecular methods to study natural communities of microbes including those found in activated sludge has revolutionised our ideas on their composition. Even so, many engineers (with some justification it has to be said) would claim that the microbiologists have promised much but in reality have contributed little to our understanding of how these plants work, or how their operational efficiencies might be improved. They could argue that all the microbiologist has achieved is to add to the confusion by showing that the microbial communities are far more diverse than were previously thought likely (Amann et al., 1996, 1998; Snaidr et al., 1997; Seviour &amp; Blackall, 1999), but without suggesting how this information might be beneficial to the operators faced with the more mundane daily tasks of running these plants..

Microbiology of the 'G-bacteria' in activated sludge

This review discusses a group of bacteria, the ‘G-bacteria’, which have a distinctive morphology of cocci in tetrads, sheets or clusters, that are seen in large numbers in many activated sludge biomass samples. Isolates of ‘G-bacteria’ that have been grown axenically are phylogenetically diverse. The Gram-negative members include several α- and β-proteobacteria, among which is the genus Amaricoccus, while the Gram-positive ‘G-bacteria’ contain several members of the actinobacteria. It is probable that other, as yet uncharacterized, ‘G-bacteria’ exist in activated sludge. The hypothesis that these ‘G-bacteria’ are detrimental to the process of enhanced biological phosphate removal by competing for substrates anaerobically with the phosphate-accumulating bacteria in such systems, based as it is largely on mixed-culture studies, receives little support from studies using those available in pure culture. The evidence on which these conclusions are founded is discussed, as are the arguments used to explain why these ‘G-bacteria’ all appear to thrive under conditions found in certain activated sludge systems