In English

Modulation of Enzymatic Activity -Case Study for Lytic Polysaccharide Monooxygenases

Vasileios Diamantopoulos
Göteborg : Chalmers tekniska högskola, 2017. 88 s.
[Examensarbete på avancerad nivå]

Lignocellulosic biomass is one of the most promising alternative resources for production of biofuels and added valued products. Conversion of lignocellulosic biomass into fermentable sugars is a very important step in lignocellulosic ethanol production. Saccharification of biomass using enzymes, called cellulases, is an attractive process but still, there is a great deal of scope for research to improve the enzymatic conversion efficiency. The efficiency of the saccharification is based on advances in the enzymatic cocktail ingredients, of which one of the most significant is the recent inclusion of Lytic polysaccharide monooxygenases (LPMOs). LPMOs are of increased biotechnological and scientific interest due to their implication in lignocellulosic biomass decomposition as they are the first enzymes that act to the crystalline cellulose making the substrate easier accessible to the other enzymes for the complete decomposition. Through the years, after the discovery of LPMOs, information about them that they have been published are about their classification, their structure, the identification of cooper as the metal in their active site, their mechanism, and what activates them. In this project, the effect of a plant extract that comes for a persimmon fruit to fungal LPMOs and to beta-glycosidase was investigated. The overall aim was the search of a modulator, which can be either an inhibitor or an activator, with the plant extract as a source for modulators. For this purpose, saccharification experiments were done using cellulose as substrate and LPMO and beta-glucosidase as enzymes. Also, fractionation of the plant extract took place using liquid-liquid extraction. With the saccharification experiments the effect of the plant extract and the fractions of it were tested on these two enzymes. Last the effect on tannins on these two enzymes was tested using dilutions of tannic acid in the saccharification experiments. It is concluded that the plant extract and the tannic acid has an inhibitory effect to the LPMOs and beta-glucosidase, with higher effect to LPMOs.

Nyckelord: Cellulose, cellulases, LPMOs, PASC, plant extract, liquid-liquid extraction, tannic acid

Publikationen registrerades 2017-11-16. Den ändrades senast 2017-11-16

CPL ID: 253191

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