Comparison of PCR-DGGE and Selective Plating Methods for Monitoring the Dynamics of a Mixed Culture Population in Synthetic Brewery Wastewater

Abstract

Enrichment of an activated sludge inoculum in synthetic brewery wastewater, which included glucose, maltose, and ethanol, was conducted in batch experiments to identify the dominant microbes present, to determine methodologies capable of monitoring the mixed culture population dynamics, and to determine the consortium's substrate degradation behavior. These results and methodologies were subsequently used in the determination of the population dynamics of suspended and attached microorganisms in a sequencing batch system in the second part of this research work. The three-membered microbial community comprised two bacterial and one fungal species that were identified as Acinetobacter sp., Enterobacter sp., and Candida sp. PCR-DGGE and plating on selective media were used to track the population dynamics of the consortium during the degradation of different substrates in synthetic wastewater containing glucose, maltose, and ethanol. Enterobacter sp. could degrade glucose and maltose but not ethanol, whereas Acinetobacter and Candida could degrade all three carbon sources. In buffered batch mixed culture experiments, Enterobacter was the predominant bacterium until the sugar concentrations decreased to levels that enabled Acinetobacter and Candida to degrade ethanol. PCR-DGGE was effective for detecting the dominant species, but culture-based methods were more accurate for monitoring the population dynamics of these microorganisms during growth in the wastewater medium.

Quantifying nitrous oxide production pathways in wastewater treatment systems using isotope technology – A critical review

“…Studying the expression of functional genes via mRNA measurement is a viable alternative for studying the regulation of pathways. Compared with DNAbased Denaturing Gradient Gel Electrophoretic analysis (DGGE), which is effective for analyzing the composition of species like the nitrifying and denitrifying bacterial populations (Hu et al 2011, Tam et al 2005, mRNA based transcription analysis can estimate microbial activities. This is because, firstly mRNA is transcribed from functional DNA, and secondly, the short half-life of mRNA in prokaryotes (Philippot and Hallin 2005) can reflect the regulation processes.…”

Craft Brewery Wastewater Treatment in a Scalable Microbial Fuel Cell Stack

“…The synthetic brewery wastewater medium was prepared by dissolving the following materials in tap water: 1 g L −1 malt extract, 0.5 g L −1 yeast extract, 0.15 g L −1 peptone, 0.86 g L −1 maltodextrin, 2.2 g L −1 (NH 4 ) 2 SO 4 , 2.8 mL L −1 ethanol, 0.08 g L −1 NaH 2 PO 4 , and 0.14 g L −1 Na 2 HPO 4 (70167, 70161, P6838, 419672, A4418, E7023, S3139, S9763, Merck Mexico, Company, San Andres Atoto, Naucalpan de Juárez, Mexico) [26]. This SBW had an initial COD of 1980 ± 17 mg L −1 and was based on wastewater samples obtained from a craft brewery in Mérida, Yucatan, Mexico.…”

“…Nitrogen was used as carrier gas with a flow rate of 1 mL min −1 ; for FID, hydrogen gas, 45 mL min −1 , and extra dry air, 450 mL min −1 , were used. The operating temperatures were 230 • C for the injector, 150, 180, and 230 • C for the oven, and 230 • C in the detector, splitless mode [26,27]. Acetic, propionicand butyric acid were used as standards (45754, P1386, B103500 Merck Mexico, Company, San Andres Atoto, Naucalpan de Juárez, Mexico).…”