Formation and final composition of the bacterial flora of a dairy waste activated sludge

Respiratory quinone profiles as tools for identifying different bacterial populations in activated sludge.

“…Many investigators have identified predominant activated sludge bacteria with such Q-8-containing bacteria as Alcaligenes, Comamonas, and certain members of Pseudoronas (4)(5)(6)(7)(8)10). This is the case in the present study.…”

“…GLIDE (15) has already reported that cytophagas occur in high numbers in sewage activated sludge. The occurrence of MK-8(H2) and other hydrogenated menaquinones in activated sludge is probably due to the presence of the coryneform and nocardioform bacteria, which have been commonly found in wastewater treatment systems as reported here and elsewhere (4)(5)(6)(7)(8)(10)(11)(12). However, the similarity in menaquinone profiles between the predominant isolates and the sludges was not so pronounced in comparison with the results for their ubiquinone patterns.…”

“…The accurate identification of sludge-derived bacterial strains is difficult and time-consuming work for investigators in this field, partly because they have to examine a wide variety of the isolates possibly including taxonomically unknown species and partly because there is the long-confused status of the taxonomy of several bacterial groups such as the so-called Flavobacteriun-Cytophaga complex. While bacterial strains isolated from activated sludge have been usually identified on the basis of their morphological, physiological, and biochemical characteristics (4)(5)(6)(7)(8)(9)(10)(11)(12), several workers also attempted to identify their isolates by computerassisted numerical cluster analysis (13), by use of species-specific fluorescent antibodies (14), and by chemotaxonomic methods (15,16). Although such pure culture studies are useful for the determination of the bacterial flora of activated sludge, they only provide limited information about the "countable and cultivable" bacterial population rather than the total population.…”

A possible effect of cellulose-decomposition on soil bacterial flora.

“…This also clearly explains the phenomenon reported in a previous paper (22) : of all bacterial groups, the population of the gram-negative bacteria was the one most closely related to the rate of CO2 evolution in the soil with added cellulose powder, and this may reflect the utilization of simple sugars derived from cellulose powder by the gram-negative bacteria. The predominance of gram-negative bacteria in soil enriched with organic compounds such as carbohydrates has been reported by many authors (23)(24)(25)(26)(27). The low level in plot 2 at 35 days of populations of the strains utilizing simple sugars can not be explained by the shortage of decomposition products from cellulose powder, since considerable amounts of reducing sugars occurred then in that plot (see the next section).…”

Studies on bacterial activities in aerobic and anaerobic waste water purification

“…While settling down these aggregates will attach to one another and form larger flocs. On repeating this procedure while retaining the flocs formed, resuming the aeration and supplying increasing amounts of waste water, large amounts of activated sludge will be produced (Adamse, 1968a).…”