High temperature utilization of PAM and HPAM by microbial communities enriched from oilfield produced water and activated sludge

Carolina Berdugo-Clavijo,Bill O’Neil,Lisa M Gieg,Arindom Sen,Mojtaba Seyyedi,Harvey Quintero

doi:10.1186/s13568-019-0766-9

Carolina Berdugo-Clavijo, Bill O’Neil + Show 4 more

Open Access

https://doi.org/10.1186/s13568-019-0766-9

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Journal: AMB Express	Publication Date: Apr 9, 2019
Citations: 11	License type: open-access

Affiliation: University of Calgary

Abstract

Non-hydrolyzed polyacrylamide (PAM) and partially hydrolyzed polyacrylamide (HPAM) are commonly used polymers in various industrial applications, including in oil and gas production operations. Understanding the microbial utilization of such polymers can contribute to improved recovery processes and help to develop technologies for polymer remediation. Microbial communities enriched from oilfield produced water (PW) and activated sludge from Alberta, Canada were assessed for their ability to utilize PAM and HPAM as nitrogen and carbon sources at 50 °C. Microbial growth was determined by measuring CO2 production, and viscosity changes and amide concentrations were used to determine microbial utilization of the polymers. The highest CO2 production was observed in incubations wherein HPAM was added as a nitrogen source for sludge-derived enrichments. Our results showed that partial deamination of PAM and HPAM occurred in both PW and sludge microbial cultures after 34 days of incubation. Whereas viscosity changes were not observed in cultures when HPAM or PAM was provided as the only carbon source, sludge enrichment cultures amended with HPAM and glucose showed significant decreases in viscosity. 16S rRNA gene sequencing analysis indicated that microbial members from the family Xanthomonadaceae were enriched in both PW and sludge cultures amended with HPAM or PAM as a nitrogen source, suggesting the importance of this microbial taxon in the bio-utilization of these polymers. Overall, our results demonstrate that PAM and HPAM can serve as nitrogen sources for microbial communities under the thermophilic conditions commonly found in environments such as oil and gas reservoirs.

Highlights

Non-hydrolyzed polyacrylamide (PAM) and partially hydrolyzed polyacrylamide (HPAM) are frequently used in many industrial applications including waste water treatment processes (Guezennec et al 2015), soil conditioning and erosion control (Levy and Warrington 2015), and oil and gas operations
CO2 accumulation in the sludge enrichments amended with either HPAM or PAM was higher than CO2 production in the produced water (PW) enrichments (Fig. 2) suggesting that the community enriched from the sludge sample had greater capability for polymer utilization
Previous studies have shown the ability of microorganisms to utilize PAM and HPAM under mesophilic conditions, but this is the first report to show that microbial PAM or HPAM utilization is possible under thermophilic conditions (50 °C)

Summary

Introduction

Non-hydrolyzed polyacrylamide (PAM) and partially hydrolyzed polyacrylamide (HPAM) are frequently used in many industrial applications including waste water treatment processes (Guezennec et al 2015), soil conditioning and erosion control (Levy and Warrington 2015), and oil and gas operations. In the latter sector, these polymers are used as thickening agents and friction reducers for enhanced oil recovery and hydraulic fracturing. The cleavage of the carbon–carbon bonds in PAM or HPAM has not been unequivocally demonstrated, the conversion of amide (NH2) groups into carboxylic acid (COOH) has been repeatedly shown using approaches such as FT-IR, LC/MS, and GC/MS analyses (Ma et al 2008; Liu et al 2012; Dai et al 2014; Yu et al 2015; Sang et al 2015)

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