Effect of bioaugmentation and biostimulation on sulfate-reducing column startup captured by functional gene profiling

Abstract

Sulfate-reducing permeable reactive zones (SR-PRZs) depend upon a complex microbial community to utilize a lignocellulosic substrate and produce sulfides, which remediate mine drainage by binding heavy metals. To gain insight into the impact of the microbial community composition on the startup time and pseudo-steady-state performance, functional genes corresponding to cellulose-degrading (CD), fermentative, sulfate-reducing, and methanogenic microorganisms were characterized in columns simulating SR-PRZs using quantitative polymerase chain reaction (qPCR) and denaturing gradient gel electrophoresis (DGGE). Duplicate columns were bioaugmented with sulfate-reducing or CD bacteria or biostimulated with ethanol or carboxymethyl cellulose and compared with baseline dairy manure inoculum and uninoculated controls. Sulfate removal began after ~ 15 days for all columns and pseudo-steady state was achieved by Day 30. Despite similar performance, DGGE profiles of 16S rRNA gene and functional genes at pseudo-steady state were distinct among the column treatments, suggesting the potential to control ultimate microbial community composition via bioaugmentation and biostimulation. qPCR revealed enrichment of functional genes in all columns between the initial and pseudo-steady-state time points. This is the first functional gene-based study of CD, fermentative and sulfate-reducing bacteria and methanogenic archaea in a lignocellulose-based environment and provides new qualitative and quantitative insight into startup of a complex microbial system.

Reactores Bioquímicos Pasivos: Una alternativa biotecnológica para la remediación de drenajes ácidos de mina

“…La mezcla reactiva debe contener un inóculo de microorganismos que favorezcan la degradación de celulosa y el establecimiento de las condiciones sulfato reductoras. En estudios por lotes se ha determinado que cuando se utiliza un buen inóculo, la remoción de sulfato y la producción de sulfuros se realiza en períodos más cortos (Pereyra et al, 2012). Como inóculo se puede utilizar sedimentos de lagos y de ríos contaminados con DAM en donde se encuentren microorganismos aerobios que favorezcan el rápido consumo de oxígeno y nitrato, así como organismos anaerobios que se establezcan en el reactor (Biermann et al, 2014).…”

“…Para el caso de las bacterias celulolíticas, la hidrólisis de celulosa es catalizada por enzimas pertenecientes al grupo de las glucosidasas, las cuales están dividas según su estructura y función en familias de enzimas. La mayoría de las glucosidasas de microorganismos anaerobios pertenecen solo a tres familias: 5, 9 y 48 (Pereyra et al, 2012). La familia 48 incluye en su mayoría exonucleasas, codificadas por el gen cel48, de única copia en los genomas de los microorganismos celulolíticos (Hua et al, 2018).…”

“…La cuantificación de los genes funcionales dsrA, cel48 y hydA por qPCR ha permitido el estudio de su dinámica bajo la influencia de diferentes factores que determinan la eficiencia de los RBP. En previos estudios con estos genes se ha demostrado cómo la composición de los substratos orgánicos (Hiibel et al, 2011), el efecto de la bioaumentación y bioestimulación (Pereyra et al, 2012), las condiciones medio ambientales y de operación (Vásquez et al, 2018) de los biorreactores pueden incrementar las comunidades microbianas, y por lo tanto el éxito para la remoción de sulfatos y metales.…”

Decline in Performance of Biochemical Reactors for Sulphate Removal from Mine-Influenced Water is Accompanied by Changes in Organic Matter Characteristics and Microbial Population Composition

“…Some previous attempts have been made to identify key functional groups and their activity [21]. The types of microbes introduced into BCRs at start-up influence their operation [22], with inocula previously acclimated to high-sulphate environments performing better than sources obtained from non-sulphate environments, such as livestock manure and anaerobic digesters [23].…”

Organoheterotrophic Bacterial Abundance Associates with Zinc Removal in Lignocellulose-Based Sulfate-Reducing Systems

“…2 The composition and dynamics of coupled organoheterotrophic and sulfate-reducing communities has been explored previously through a variety of molecular approaches including quantitative PCR, 3,4 T-RFLP, 5 clone libraries, 6 and DGGE. 4 However, these methodologies have limitations in calculating microbial diversity estimates 7,8 and phylogenetic resolution, impeding the delineation of interactions between functional guilds and their correlation to environmental and operational variables. To this end, a previously unattainable resolution can be achieved by employing high-throughput 16S rRNA gene-based phylogenetic sequencing to facilitate the identification of temporal and spatial ecological trends and the correlation to metabolic drivers of community composition.…”