Acidogenic microbial species diversity in anaerobic digesters treating different substrates

Abstract

Microbial species diversity was determined for the acidogenic populations of four different digesters treating landfill leachate, a petrochemical effluent and sewage. The digesters were a downflow fixed-bed, conventional, cold conventional and an upflow hybrid design. The 288 strains isolated from the digesters were characterized using API test systems and identifications confirmed using current taxonomic methods. The taxonomic diversity was determined using the Shannon (H′) and equitability (J′) indices. The species from the four digesters were very similar with the exception of those from the digester treating the landfill leachate. The higher diversity in the latter was probably due to the diverse composition of the leachate, suggesting that members of this population were more generalists, as opposed to the more narrowly constrained members in the other three digesters. The data indicated that in a digester environment dominated by a more specific carbon containing effluent, like a petrochemical effluent, the population becomes stenotolerant and is characterized by a lower species diversity. Such a population would not be able to cope as well with environmental fluctuations. With a more diverse substrate like the landfill leachate, generalists, having a wider range for environmental variables, would dominate. This is important in terms of anaerobic digester process efficiency and stability.

Effects of linoleic acid and its degradation by-products on mesophilic hydrogen production using flocculated and granular mixed anaerobic cultures

“…[36] 12 Clostridium sp. [45], Bacteroides [36], Eubacterium [37,49], and Geobacter sp. [51] 8 Clostridium sp.…”

“…[36] 2 G. Granular culture fed glucose plus LA (G3) Bacillus sp. [45] 37 Cytophaga [55] and Eubacterium sp. [37,49] 19 Clostridium sp.…”

Stenotrophomonas acidaminiphila sp. nov., a strictly aerobic bacterium isolated from an upflow anaerobic sludge blanket (UASB) reactor.

“…ecosystems, of aerobic, non-sporulating, Gram-negative, flagellated, chemo-organotrophic proteobacteria that possess a strictly respiratory energy-yielding metabolism (Britz et al, 1994 ;Hakulinen et al, 1985 ;Ng et al, 1994 ;Toerien & Hattingh, 1969). A wide diversity of genera, including Stenotrophomonas, are members of this heterogeneous group with versatile metabolisms.…”

“…Stenotrophomonas species are common inhabitants of a wide variety of natural and artificial environments such as water, sediments, plant rhizospheres, corroded metal surfaces, waste-gas biofilters, aquaculture tanks, oilfields, sewage and anaerobic reactors (Aznar et al, 1992 ;Boonchan et al, 1998 ;Borowicz et al, 1995 ;Britz et al, 1994 ;Finkmann et al, 2000 ;Hauben et al, 1999 ;Juhnke et al, 1987 ;Lambert et al, 1990 ;Leifert & Waites, 1992 ;Wallace et al, 1994 ;Wilkinson et al, 1994) and can be opportunistic human pathogens (Drancourt et al, 1997 ;Denton & Kerr, 1998).…”

Effect of a water extract of Moringa oleifera seeds on the hydrolytic microbial species diversity of a UASB reactor treating domestic wastewater

“…1985 ), its effect on micro‐organisms involved in anaerobic treatment processes in general and upflow anaerobic sludge blanket (UASB) reactors in particular has not yet been reported. It is, however, important to understand the possible implications of WEMOS on a biological treatment system since the substrate composition influences the digester communities ( Britz et al . 1994 ; Howgrave‐Graham et al .…”