Feruloyl esterases - Evaluation of their potential for biotechnological applications
Based on functional annotations, targets originating from microorganisms found in diverse ecological niches were selected. In one study, five putative feruloyl esterases/tannases from two Aspergillus fungi were selected. In another study, two multi-domain enzymes displaying two predicted esterase domains from the polysaccharide utilization loci of bacteria in the Bacteroidetes phylum were investigated. The enzymes displayed differences in their preferred reaction conditions (pH, temperature), molecular weights, predicted isoelectric points, as well as substrate preferences. The impact of the production host on the final enzyme properties was investigated in an additional study. We demonstrated that in the case of glycosylated enzymes, careful selection of the production host is crucial for thermostability. Studying immobilization, data showed that the best immobilization yield and the best immobilized enzyme performance were not achieved in the same conditions for any of the enzyme-support couples tested. Investigations of immobilized enzyme transesterification or hydrolysis activities clearly demonstrated that immobilization does affect the catalytic activity of enzymes. In the current status of our knowledge, the way an enzyme is affected by immobilization is not predictable. Increased knowledge about esterase structures, reaction mechanisms and surface properties may however allow such predictions in the future. This thesis contributes to increasing the available information about esterases, and in particular feruloyl esterases.
carbohydrate active enzyme family 1
acetyl xylan esterase
polysaccharide utilization loci
Chalmers, Biologi och bioteknik, Industriell bioteknik
Feruloyl esterase immobilization in mesoporous silica particles and characterization in hydrolysis and transesterification
BMC Biochemistry,; Vol. 19(2018)
Artikel i vetenskaplig tidskrift
Glycosylation influences activity, stability and immobilization of the feruloyl esterase 1a from Myceliophthora thermophila
AMB Express,; Vol. 9(2019)
Artikel i vetenskaplig tidskrift
Kmezik C, Bonzom C, Olsson L, Mazurkewich S, Larsbrink J. Investigation of multi-domain esterases from soil and gut Bacteroidetes involved in xylan metabolism.
Bonzom C, Thörn C, Anasontzis G, Schild L, Olsson L. Investigation of five putative esterases from Aspergillus glaucus and Aspergillus zonatus.
The enzymes that I studied during my thesis work, called feruloyl esterases, are involved in the degradation of plant material. These enzymes can therefore be found in microorganisms living in digestive tracts, as well as in microorganisms living in soil or growing on trees. Because they can be encountered in very diverse environments and conditions (i.e. pH, temperature) feruloyl esterases with various preferences in term of reaction conditions exist. Because of the reaction they catalyze, feruloyl esterases are of interest to various industries such as bio-refineries, paper mills, or food and feed industries. By modifying the reaction conditions, it is possible to change the reaction direction and make feruloyl esterases link together compounds they otherwise separate. The products of this type of synthetic reaction can be of interest for cosmetic and pharmaceutical industries. In addition, enzyme-based processes are usually conducted at milder temperatures and require less harmful chemicals than the corresponding chemical ones.
Despite the progress made in the past decades, enzymes remain costly to use. In order to decrease the economic impact of using enzymes in industrial processes, several strategies can be used. During my thesis work, I investigated novel esterases, with the aim of finding better ones (e.g. reacting faster, lasting longer). I also looked into the impact of the chosen microorganism for production. In doing so, I observed that some sugar-chain decorations, N‑glycosylation, which some microorganisms add on enzymes during production, are important for the activity and stability of these enzymes. Interestingly, I was able to demonstrate that the length of the sugar-chains changed the preferred reaction temperature of one feruloyl esterase by 10°C.
Another way of reducing the costs of using enzymes is to reuse them. In order to be able to do so we can attach them onto supports, a technique that is called enzyme immobilization. During my project, I used a support that is made of silica and possesses a porous network. The pores of the support allow the immobilization of high amounts of enzyme and can also shelter enzymes. I studied the impact of being immobilized in porous silica support on the activity of some feruloyl esterases. I also used these immobilized feruloyl esterases to evaluate their ability to perform synthetic reactions.
Altogether, these different aspects (picking the right enzyme, producing it efficiently and reusing it after immobilization) will contribute to make the use of enzymes more economically feasible. This will allow for the development of industrial enzyme-based processes that are more respectful of our planet.
Biokatalys och enzymteknik
Chalmers infrastruktur för masspektrometri
Livsvetenskaper och teknik (2010-2018)
Doktorsavhandlingar vid Chalmers tekniska högskola. Ny serie: 4623
Chalmers tekniska högskola
FB-salen, Fysikgården 4, Chalmers
Opponent: Peter Westh, Technical university of Denmark, Denmark