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Fed-batch growth of Rhizopus oryzae : eliminating ethanol formation by controlling glucose addition
Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2021.
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| Format: | Thesis |
| Language: | English |
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University of Pretoria
2021
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| _version_ | 1867613494900162560 |
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| access_status_str | Open Access |
| author2 | Nicol, Willie |
| author_browse | Nicol, Willie |
| author_facet | Nicol, Willie |
| collection | Thesis |
| dc_rights_str_mv | © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. |
| description | Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2021. |
| format | Thesis |
| id | oai:repository.up.ac.za:2263/81076 |
| institution | University of Pretoria (South Africa) |
| language | English |
| last_indexed | 2026-06-10T12:37:02.876Z |
| license_str | Other — see source repository |
| provenance_str_mv | Harvested via OAI-PMH from UPSpace — University of Pretoria Institutional Repository |
| publishDate | 2021 |
| publishDateRange | 2021 |
| publishDateSort | 2021 |
| publisher | University of Pretoria |
| publisherStr | University of Pretoria |
| record_format | dspace |
| source_str | UPSpace — University of Pretoria Institutional Repository |
| spelling | oai:repository.up.ac.za:2263/81076 Fed-batch growth of Rhizopus oryzae : eliminating ethanol formation by controlling glucose addition Nicol, Willie nw.dejongh.vii@gmail.com De Jongh, Nicolaas Willem Rhizopus oryzae respiration quotient controlled substrate addition Crabtree effect fumarate production fed-batch reactor UCTD Engineering, built environment and information technology theses SDG-03 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Dissertation (MEng (Chemical Engineering))--University of Pretoria, 2021. Rhizopus oryzae is a prominent strain for producing fumarate, where biomass growth precedes fumarate production. The natural bio film growth of R. oryzae as fungal mat was investigated using different glucose addition strategies in a novel fed-batch fermenter. Batch growth was compared through three fed-batch runs, each with a different glucose addition strategy. The fed-batch runs involved a constant glucose feed (CGF) of 0.075 g h-1 and controlled glucose feeds in order to keep the respiration quotient (RQ) at either 1.3 mol CO2 mol-1 O2 (RQ1.3) or 1.1 mol CO2 mol-1 O2 (RQ1.1). Ethanol overflow via the established Crabtree mechanism was completely negated for the CGF and RQ1.1 runs, while the batch and RQ1.3 runs exhibited significant ethanol formation. Biomass yield on glucose was found to be 0.476 g g-1 (RQ1.1), 0.194 g g-1 (RQ1.3), 0.125 g g-1 (CGF) and 0.144 g g-1 (batch). The results indicate a three-fold improvement in biomass yield when comparing the batch run with the RQ1.1 run. In addition, the RQ1.1 run resulted in zero detectable byproducts, unlike the batch scenario where pyruvate and fumarate were associated with ethanol formation. Clear evidence is provided that glucose overflow can be fully eliminated during R. oryzae growth, significantly affecting the biomass yield on glucose. University of Pretoria postgraduate bursary CSIR Inter-bursary Programme mi2026 Chemical Engineering MEng (Chemical Engineering) Unrestricted SDG-03: Good health and well-being SDG-09: Industry, innovation and infrastructure SDG-12: Responsible consumption and production 2021-07-30T13:13:56Z 2021-07-30T13:13:56Z 2021 2021-05 Dissertation * S2021 http://hdl.handle.net/2263/81076 en © 2019 University of Pretoria. All rights reserved. The copyright in this work vests in the University of Pretoria. No part of this work may be reproduced or transmitted in any form or by any means, without the prior written permission of the University of Pretoria. application/pdf University of Pretoria |
| spellingShingle | Rhizopus oryzae respiration quotient controlled substrate addition Crabtree effect fumarate production fed-batch reactor UCTD Engineering, built environment and information technology theses SDG-03 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 Fed-batch growth of Rhizopus oryzae : eliminating ethanol formation by controlling glucose addition |
| title | Fed-batch growth of Rhizopus oryzae : eliminating ethanol formation by controlling glucose addition |
| title_full | Fed-batch growth of Rhizopus oryzae : eliminating ethanol formation by controlling glucose addition |
| title_fullStr | Fed-batch growth of Rhizopus oryzae : eliminating ethanol formation by controlling glucose addition |
| title_full_unstemmed | Fed-batch growth of Rhizopus oryzae : eliminating ethanol formation by controlling glucose addition |
| title_short | Fed-batch growth of Rhizopus oryzae : eliminating ethanol formation by controlling glucose addition |
| title_sort | fed batch growth of rhizopus oryzae eliminating ethanol formation by controlling glucose addition |
| topic | Rhizopus oryzae respiration quotient controlled substrate addition Crabtree effect fumarate production fed-batch reactor UCTD Engineering, built environment and information technology theses SDG-03 Engineering, built environment and information technology theses SDG-09 Engineering, built environment and information technology theses SDG-12 |
| url | http://hdl.handle.net/2263/81076 |