Document Type

Theses, Ph.D

Rights

Available under a Creative Commons Attribution Non-Commercial Share Alike 4.0 International Licence

Disciplines

4.2 ANIMAL AND DAIRY SCIENCE, Agricultural biotechnology and food biotechnology

Publication Details

A THESIS SUBMITTED TOTHE TECHNOLOGICAL UNIVERSITY DUBLIN FOR THE AWARD OF DOCTOR OF PHILOSOPHY

Abstract

Hydrolytic enzymes, such as pectinase and xylanase, maybe harnessed for numerous industrial applications in food industry. Therefore, economic factors such as achievement of optimum yieldsandoverall production costs, in addition to biocatalyst instability,are the main obstacles tothe industrial production and exploitation of a enzymes. For example, microbially-derived enzymes are typically produced in fermenters using expensive growth media, which may account for 30 to 40% of the production cost, and such expense may be compounded further by downstream processing operations.To counter such disadvantages, the major trend in industrial utilization of enzymes in cost-sensitive processes has been to immobilize such biocatalysts on a solid support, thereby mediating the key advantage of reusability.A complementary approachin recent years has been to target reduction inupstream processing costs in enzyme production by incorporation of negative cost raw materialsinto the medium composition, Food waste such as Brewers’ spent grain (BSG) constitutes anenvironmental problem in Ireland buthas the potentialtoprovidea continuous and renewable feedstock (carbon source) for production of industrial enzymes, thereby reducing production costs. However, a significant barrier to the exploitation of lignocellulose is the recalcitrant nature of the biomass, which usually requires expensive pre-treatment to release sugars.The key goal of this study was to pursue an integrated upstream and downstream approach to develop novel immobilized enzyme preparations for the juice industry. The aim of the project was achievedthrough the following measures:•Screening and isolation of microrganisms which produced xylanases and pectinases possessing a physico-chemical profile of relevance to the fruit juice sector. •Development of an optimal pretreatment strategy for BSGthat would enhance their suitability as a carbon source for the upstream processing of the microbe which produced the enzymes. •Optimisation ofthe upstream processing for the production of as the pectinaseand xylanasecatalysts.•Investigation of a novel method for enzyme immobilization, and establishment of optimal process performance characteristics for use in juice clarification

DOI

https://doi.org/10.21427/g2ey-hk88

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