\u3cem\u3emcrA\u3c/em\u3e Gene Abundance Correlates with Hydrogenotrophic Methane Production Rates in Full-scale Anaerobic Waste Treatment Systems

Anaerobic treatment is a sustainable and economical technology for waste stabilization and production of methane as a renewable energy. However, the process is under-utilized due to operational challenges. Organic overload or toxicants can stress the microbial community that performs waste degradation, resulting in system failure. In addition, not all methanogenic microbial communities are equally capable of consistent, maximum biogas production. Opinion varies as to which parameters should be used to monitor the fitness of digester biomass. No standard molecular tools are currently in use to monitor and compare full-scale operations. It was hypothesized that determining the number of gene copies of mcrA, a methanogen-specific gene, would positively correlate with specific methanogenic activity (SMA) rates from biomass samples from six full-scale anaerobic digester systems. Positive correlations were observed between mcrA gene copy numbers and methane production rates against H2 : CO2 and propionate (R2 = 0·67–0·70, P \u3c 0·05) but not acetate (R2 = 0·49, P \u3e 0·05). Results from this study indicate that mcrA gene targeted qPCR can be used as an alternate tool to monitor and compare certain methanogen communities in anaerobic digesters

Complete Genome of Rhodococcus pyridinivorans SB3094, a Methyl-Ethyl-Ketone-Degrading Bacterium Used for Bioaugmentation

Here, we present the complete genome of Rhodococcus pyridinivorans SB3094, a methyl-ethyl-ketone (MEK)-degrading strain used for bioaugmentation relating to the treatment of wastewater contamination with petrochemical hydrocarbons. The genome highlights important features for bioaugmentation, including the genes involved in the degradation of MEK

Complete Genome Sequences of Pseudomonas monteilii SB3078 and SB3101, Two Benzene-, Toluene-, and Ethylbenzene-Degrading Bacteria Used for Bioaugmentation

Pseudomonas monteilii SB3078 and SB3101 are benzene-, toluene-, and ethylbenzene-degrading strains used for bioaugmentation in relation to treatment of wastewater contaminated with petrochemical hydrocarbons. Complete genome sequencing of the bioaugmentation strains confirms that they are very closely related (100.0% average nucleotide identity). Both strains contain extensive integration of phage elements, with the main difference being insertion of additional phage elements in the SB3078 genome

Survival and activity of individual bioaugmentation strains

Successful application of bioaugmentation for enhanced degradation of environmental pollutants is often limited by the lack of methods to monitor the survival and activity of individual bioaugmentation strains. However, recent advancements in sequencing technologies and molecular techniques now allow us to address these limitations. Here a complementing set of general applicable molecular methods are presented that provides detailed information on the performance of individual bioaugmentation strains under in situ conditions. The approach involves genome sequencing to establish highly specific qPCR and RT-qPCR tools for cell enumerations and expression of involved genes, stable isotope probing to follow growth on the target compounds and GFP-tagging to visualize the bioaugmentation strains directly in samples, all in combination with removal studies of the target compounds. The concept of the approach is demonstrated through a case study involving degradation of aromatic hydrocarbons in activated sludge augmented with the bioaugmentation strain Pseudomonas monteilii SB3078