{"id":{"repo_id":"birmingham","oai_identifier":"oai:etheses.bham.ac.uk:547"},"canonical_url":"https://search.dev.ndltd.org/etd/birmingham/oai:etheses.bham.ac.uk:547","repository":{"repo_id":"birmingham","name":"University of Birmingham","base_url":"https://etheses.bham.ac.uk/cgi/oai2"},"display":{"title":"Optimisation of the preservation of microbial cell banks for enhanced fermentation process performance","abstract":"This work discusses optimisation of the cryopreservation of Bacillus licheniformis cell banks, used as inoculum for α-amylase producing 5 L batch fermentations. The effect of the presence of various cryopreservants including glycerol, Tween 80 and dimethyl sulphoxide on final fermentation performance measured by biomass and α-amylase concentration was investigated using optical density, dry cell weight, colony forming units, and multi-parameter flow cytometry. The application of multi-parameter flow cytometry using the fluorophores DiBac\\(_4\\)(3) and PI allowed real time viability measurements of individual microbial cells to be monitored before and after cryopreservation and during the fermentation process; viability here being defined as a cell having an intact and fully polarised cytoplasmic membrane. It was found that the concentration and type of cryopreservant used had a significant effect on microbial cell physiology and population heterogeneity during resuscitation recovery immediately after thawing. Cell banks prepared with Tween 80 were fastest to recover after freezing in comparison to cell banks prepared with dimethyl sulphoxide which showed the slowest growth rates. Interestingly cells preserved in glycerol recovered at a similar rate to cells frozen without cryopreservant. Despite different responses to the freezing process when each cell bank was used as inoculum for 5 L batch fermentations very little difference was noticed in overall process performance with respect to α-amylase production, growth rate and final biomass concentration.","abstract_html":"This work discusses optimisation of the cryopreservation of Bacillus licheniformis cell banks, used as inoculum for α-amylase producing 5 L batch fermentations. The effect of the presence of various cryopreservants including glycerol, Tween 80 and dimethyl sulphoxide on final fermentation performance measured by biomass and α-amylase concentration was investigated using optical density, dry cell weight, colony forming units, and multi-parameter flow cytometry. The application of multi-parameter flow cytometry using the fluorophores DiBac<span class=\"etd-inline-math\"><sub>4</sub></span>(3) and PI allowed real time viability measurements of individual microbial cells to be monitored before and after cryopreservation and during the fermentation process; viability here being defined as a cell having an intact and fully polarised cytoplasmic membrane. It was found that the concentration and type of cryopreservant used had a significant effect on microbial cell physiology and population heterogeneity during resuscitation recovery immediately after thawing. Cell banks prepared with Tween 80 were fastest to recover after freezing in comparison to cell banks prepared with dimethyl sulphoxide which showed the slowest growth rates. Interestingly cells preserved in glycerol recovered at a similar rate to cells frozen without cryopreservant. Despite different responses to the freezing process when each cell bank was used as inoculum for 5 L batch fermentations very little difference was noticed in overall process performance with respect to α-amylase production, growth rate and final biomass concentration.","abstract_has_math":true,"creators":["Hancocks, Nichola Helen"],"institution":"University of Birmingham","degree_name":"d_ph","degree_level":"d_ph","degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2011,"date_issued":"2011-12","date_published":"2011-12","updated_at":"2026-07-24T01:10:58Z","subjects":["TP Chemical technology"],"languages":[],"rights":[],"rights_urls":[],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.sponsor","label":"Sponsor","values":["na"]},{"key":"dc:creator","label":"Author","values":["Hancocks, Nichola Helen"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date","label":"Dc Date","values":["2011-12"]},{"key":"dc:date.issued","label":"Date","values":["2011-12"]},{"key":"dc:publisher.department","label":"Dc Publisher Department","values":["College of Engineering & Physical Sciences","School of Chemical Engineering"]},{"key":"dc:publisher.institution","label":"Dc Publisher Institution","values":["University of Birmingham"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["http://etheses.bham.ac.uk//id/eprint/547/"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"dc:type.qualificationlevel","label":"Dc Type Qualificationlevel","values":["d_ph"]},{"key":"dc:type.qualificationname","label":"Dc Type Qualificationname","values":["d_ph"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["TP Chemical technology"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://etheses.bham.ac.uk//id/eprint/547/1/Decl_IS_hancocks10PhD.pdf","http://etheses.bham.ac.uk//id/eprint/547/2/Hancocks10PhD.pdf"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["This work discusses optimisation of the cryopreservation of Bacillus licheniformis cell banks, used as inoculum for α-amylase producing 5 L batch fermentations. The effect of the presence of various cryopreservants including glycerol, Tween 80 and dimethyl sulphoxide on final fermentation performance measured by biomass and α-amylase concentration was investigated using optical density, dry cell weight, colony forming units, and multi-parameter flow cytometry. The application of multi-parameter flow cytometry using the fluorophores DiBac\\(_4\\)(3) and PI allowed real time viability measurements of individual microbial cells to be monitored before and after cryopreservation and during the fermentation process; viability here being defined as a cell having an intact and fully polarised cytoplasmic membrane. It was found that the concentration and type of cryopreservant used had a significant effect on microbial cell physiology and population heterogeneity during resuscitation recovery immediately after thawing. Cell banks prepared with Tween 80 were fastest to recover after freezing in comparison to cell banks prepared with dimethyl sulphoxide which showed the slowest growth rates. Interestingly cells preserved in glycerol recovered at a similar rate to cells frozen without cryopreservant. Despite different responses to the freezing process when each cell bank was used as inoculum for 5 L batch fermentations very little difference was noticed in overall process performance with respect to α-amylase production, growth rate and final biomass concentration."]},{"key":"dc:format","label":"Dc Format","values":["application/pdf"]},{"key":"dc:title","label":"Title","values":["Optimisation of the preservation of microbial cell banks for enhanced fermentation process performance"]}]}],"canonical_facts":{"dc:contributor.sponsor":["na"],"dc:creator":["Hancocks, Nichola Helen"],"dc:date":["2011-12"],"dc:date.issued":["2011-12"],"dc:description.abstract":["This work discusses optimisation of the cryopreservation of Bacillus licheniformis cell banks, used as inoculum for α-amylase producing 5 L batch fermentations. The effect of the presence of various cryopreservants including glycerol, Tween 80 and dimethyl sulphoxide on final fermentation performance measured by biomass and α-amylase concentration was investigated using optical density, dry cell weight, colony forming units, and multi-parameter flow cytometry. The application of multi-parameter flow cytometry using the fluorophores DiBac\\(_4\\)(3) and PI allowed real time viability measurements of individual microbial cells to be monitored before and after cryopreservation and during the fermentation process; viability here being defined as a cell having an intact and fully polarised cytoplasmic membrane. It was found that the concentration and type of cryopreservant used had a significant effect on microbial cell physiology and population heterogeneity during resuscitation recovery immediately after thawing. Cell banks prepared with Tween 80 were fastest to recover after freezing in comparison to cell banks prepared with dimethyl sulphoxide which showed the slowest growth rates. Interestingly cells preserved in glycerol recovered at a similar rate to cells frozen without cryopreservant. Despite different responses to the freezing process when each cell bank was used as inoculum for 5 L batch fermentations very little difference was noticed in overall process performance with respect to α-amylase production, growth rate and final biomass concentration."],"dc:format":["application/pdf"],"dc:identifier.uri":["http://etheses.bham.ac.uk//id/eprint/547/1/Decl_IS_hancocks10PhD.pdf","http://etheses.bham.ac.uk//id/eprint/547/2/Hancocks10PhD.pdf"],"dc:publisher.department":["College of Engineering & Physical Sciences","School of Chemical Engineering"],"dc:publisher.institution":["University of Birmingham"],"dc:relation.isreferencedby":["http://etheses.bham.ac.uk//id/eprint/547/"],"dc:subject":["TP Chemical technology"],"dc:title":["Optimisation of the preservation of microbial cell banks for enhanced fermentation process performance"],"dc:type":["Thesis"],"dc:type.qualificationlevel":["d_ph"],"dc:type.qualificationname":["d_ph"]},"updated_at":"2026-07-24T01:10:58Z"}