The American Chemical Society’s Green Chemistry Institute (ACS GCI) convenes five roundtables with over 40 companies from across the world to focus on the science of sustainable and green chemistry and its implementation. In this collaborative forum, companies can benchmark progress, develop standard tools, identify key research areas, award funding, give input to policysetting organizations and author papers on projects, among other initiatives.

In 2015, the ACS GCI in partnership with the hydraulic fracturing industry formed the ACS GCI Hydraulic Fracturing Roundtable (HFR) to identify opportunities for the oil and gas industry to use green chemistry and engineering in hydraulic fracturing. The Roundtable seeks to enable informed decisions about those chemicals commonly employed in hydraulic fracturing and to promote the prioritized development of more sustainable chemical alternatives. Current members include Apache Corporation, Baker Hughes (a GE Company), BASF, BJ Services, Blentech, Canadian Energy Services, Innospec and Rockwater Energy Solutions.

The HFR has identified finding an alternative biocide or another way to reduce the use of biocides in hydraulic fracturing as a key initiative. Biocides are widely used to sterilize, sanitize and disinfect surfaces in our homes, in the industrial preparation of food, the treatment of water, healthcare, and in many other areas. The oil and gas industry uses biocides in hydraulic fracturing operations to control underground bacterial growth which often leads to the formation of thick biofilms that can impede fluid flow from the well or lead to the uncontrolled release of dangerous gases such as hydrogen sulfide, a metabolic by-product of microbial respiration.

Safety and environmental contamination risks related to biocide use in the practice of hydraulic fracturing include surface spills associated with transportation, onsite storage and handling. In addition, more research is needed to better understand the sub-surface environmental fate and effects of biocides.

Many hydraulic fracturing industry operators and service companies are engaged in research and activities to lower the quantity and reduce the toxicity of hydraulic fracturing chemicals, including biocides. One approach the HFR is currently exploring is the use of enzymes to degrade biofilms and thereby reduce or eliminate the use of biocides. Enzymes provide several advantages because they are generally safer to handle, possess lower toxicity, will not persist in the environment, will not corrode machinery, and are specifically targeted for a given class of molecules. Concerns about enzymes include the fact that they are proteins and can, in a limited number of cases, cause an immune response in humans, as any foreign protein will; however, it is rare to see an allergic response or sensitization to enzymes. Also, the cost of enzymes and their shelf-life will have to be addressed; existing models show industrial engineering and production of enzymes can mitigate these concerns.

As a first step, the Roundtable has conducted a literature review, led by Nathan Wymer, PhD, an assistant professor at North Carolina Central University, to understand what is currently known about biofilms and the enzymatic degradation of biofilms. While additional research needs to be done to fully characterize and understand biofilms associated with the practice of hydraulic fracturing, it is promising that a number of enzymes are known to degrade the molecular components of typical biofilms (e.g., polysaccharides, proteins, lipids, nucleic acids). In fact, enzymes are already being employed in a number of industrial applications (e.g., biofuels, paper pulp, textiles, detergents, pharma). One major challenge of this approach will be developing enzymes that can function at the high temperature and alkalinity found within a “typical” well created by hydraulic fracturing. New advances in molecular biology are providing tools for R&D scientists to be able to modify enzymes to exhibit targeted properties such as these. Wymer believes a good platform to start enzyme engineering and optimization could be with commercially available enzymes from the laundry detergent industry which also deals with warmer temperatures and higher alkalinity.

The ACS GCI Hydraulic Fracturing Roundtable is seeking to facilitate academic research on enzymatic alternatives to biocides by partnering with scientific funding agencies and academic researchers. Historically, the ACS GCI’s Roundtables have successfully supported research through company contributions including more than $1.9 million to fund green chemistry research for the pharmaceutical industry and through federal agency funding of $800,000 related to less energy intensive alternative separations to distillation in collaboration with the ACS GCI Chemical Manufacturer’s Roundtable.

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