Investigating chlorite dismutase biocatalyst reuse using columns

Microcontaminants are compounds in water present below 1 ppm which have major long-term health impacts. Traditional treatment processes are not designed to treat these chemicals and existing treatment methods come with downsides including higher chemical input, higher energy input, production of a waste stream, use of high cost media, and/or production of toxic byproducts. Biocatalysis, using enzymes to degrade contaminants, has been proposed as a treatment method. This process would require reuse of the biocatalysts to reduce costs for continuously operated water treatment systems. To study the potential for biocatalyst reuse, experiments were conducted on a chlorite dismutase biocatalyst modified with a strep tag; this reuse system allows the biocatalyst to bind to coated resin beads that can be reused in a column system. Chlorite dismutase treats chlorite to chloride and oxygen. Activity tests were conducted in batch for the purified and attached biocatalysts and in column to determine impact of attachment on the biocatalyst’s activity and inactivation. Activity results showed no impact of tag addition, with a tagged biocatalyst Vmax of 34,600 ± 2,900 μmol chlorite min-1 μmol heme-1 and a Km of 106.6 ± 70.6 μM. The attached biocatalyst was able to reach the same maximal activity as the free biocatalyst with the introduction of a mass transfer limited region, which can be described with a kl of 0.1415 cm min-1. Column activity was difficult to measure but was similar to the attached batch result in four successful experiments. Finally, the maximum theoretical turnover number in the column system was 152,800 ± 11,800 μmol chlorite μmol heme-1. While more understanding of the inactivation kinetics is needed to enable a detailed comparison, based on the maximum theoretical turnover number, a fully loaded column is projected to be able to treat 86,000 bed volumes (equivalent to 59.7 days at design flowrate and concentration) before being fully inactivated.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Environ Engr in Civil Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2020

Author dc:creator

• Kamalanathan, Indran

Contributors dc:contributor

• Zilles, Julie L
• Guest, Jeremy S

• Biocatalysis
• Microcontaminants
• Chlorite
• Perchlorate
• Reuse

Statement dc:rights

• Copyright 2019 Indran Kamalanathan

Language dc:language

en

Handle dc:identifier

http://hdl.handle.net/2142/106430

OAI identifier oai:identifier

oai:www.ideals.illinois.edu:2142/106430