Phylogenetic and physiological characterization of organic waste-degrading bacterial communities

Abstract

One of the greatest challenges in contemporary society is to reduce and treat household solid waste. The choice of inoculum to be used for start-up in reactors that degrade organic waste is critical to the success of organic waste treatment. In this study, the functional diversity, phylogenetic identification, and biogas production of bacterial communities from six inoculum sources were investigated. We used BIOLOG EcoPlates to evaluate the metabolic abilities of the bacterial communities, followed 16S rRNA gene sequence analysis to determine the phylogenetic affiliation of the bacteria responsible for carbon consumption. We observed great diversity in the physiological profiles. Of the six inocula tested, the sludge from an upflow anaerobic sludge blanket reactor (SRU) contained the most diverse, metabolically versatile microbiota and was characterized by the highest level of biogas production. By contrast, the sludge of the anaerobic lagoon (SAL) showed the worst performance in BIOLOG EcoPlates assays, but it exhibited the most diversity and generated the second largest amount of biogas. The bacterial isolates retrieved from BIOLOG EcoPlates were characterized as aerobic and/or facultative anaerobic, and were mainly Gram-negative. Phylogenetic analysis revealed that the isolates belonged to three major phyla: Proteobacteria, Firmicutes and Actinobacteria, represented by 33 genera. Proteobacteria exhibited the most diversity. The distribution of the bacterial genera differed considerably among the six inocula. Pseudomonas and Bacillus, which are able to degrade a wide range of proteins and carbohydrates, predominated in five of the six inocula. Analysis of the bacterial communities in this study indicates that both SRU and SAL microbiota are candidates for start-up inocula in anaerobic reactors. These start-up inocula must be studied further in order to identify their practical applications in degrading organic waste.

Assessment of Changes in Microbial Communities in Different Operational Units from a Wastewater Treatment Plant

“…In another study, a heterotrophic bacteria count revealed 10 10 cfu ml -1 on TSB agar. This study indicated that for substrate utilization, cell density was important and the low number of cells required a long time for adaption to environmental conditions [38]. Our data supported this and have similar results.…”

“…But for biological activity, the pH values of ASU and ADU were near neutral in all samplings. The neutral pH values were obtained from another study for anaerobic digester units that also indicated suitable conditions [38].…”

Diversity and Antibiotic Resistance Patterns of Sphingomonadaceae Isolates from Drinking Water

“…yanoikuyae), pet-associated environments (S. panni and N. panipatense), or potato cultures (Sp. yanoikuyae) (3,4,10,15). On the other hand, some species were distinguished by susceptibility to most of the antibiotics.…”

Microbial Community Dynamics in Field-Scale Biopile Bioremediation

“…In this study we collected four samples (D1S1, D1S2, D1N1, and D1N2) flag-marked from the same biopile and analyzed for 10 months. Biolog EcoPlate assays showed that the bacterial communities from all samples utilized a variety of the 31 carbon substrates, grouped in the following classes of compounds: amines, carbohydrate complex carbon sources, carboxylic acids, amino acids, and phosphate carbon according to similar studies [7,[19][20]. The utilization of carbon sources into six substrate groups showed similar use every month, despite the temperature variations between cold and extremely hot seasons.…”

“…The autumn and winter months also registered a low metabolic activity due to decreasing pollutants, microbial community selected until that time being most probably specialized on such compounds. AWCD shows the fastest rate of carbon substrate consumption, suggesting great genetic diversity within the analized bacterial community [3,19,21].…”