{"id":{"repo_id":"vt","oai_identifier":"oai:vtechworks.lib.vt.edu:10919/32615"},"canonical_url":"https://search.dev.ndltd.org/etd/vt/oai:vtechworks.lib.vt.edu:10919/32615","repository":{"repo_id":"vt","name":"Virginia Tech","base_url":"https://vtechworks.lib.vt.edu/oai/request"},"display":{"title":"Utilization of a Microbubble Dispersion to Increase Oxygen Transfer in Pilot-Scale Baker's Yeast Fermentation Unit","abstract":"In the large-scale production of <i>Saccharomyces cerevisiae</i> (baker's yeast), oxygen transfer, which is one of the major limiting factors, is improved by using high agitation rates. However, high agitation rates subject the microorganisms to high shear stress and caused high power consumption. A microbubble dispersion (MBD) method was investigated to improve oxygen transfer at low agitation rates and thus reduce power consumption and shear stress on the microorganisms. The experiments were conducted at the 1-liter level and subsequently scaled-up to 50-liters using a constant volumetric oxygen transfer coefficient (<i>k<sub>L</sub>a</i>) method for scaling. In comparison to a conventional air-sparged fermentation, the MBD method considerably improved the cell mass yield, growth rate and power consumption in the 50-liter fermentor. Cell mass production in the MBD system at agitation rate of 150 rpm was about the same as those obtained for a conventional air-sparged system agitatid at 500 rpm. Power consumption in the conventional air-sparged system was three-fold that required for the same biomass yield in the MBD system. However, at the 1-liter scale, the MBD system did not show any significant advantage over the air-sparged system because of the high power consumption.","abstract_html":"In the large-scale production of &lt;i&gt;Saccharomyces cerevisiae&lt;/i&gt; (baker&#x27;s yeast), oxygen transfer, which is one of the major limiting factors, is improved by using high agitation rates. However, high agitation rates subject the microorganisms to high shear stress and caused high power consumption. A microbubble dispersion (MBD) method was investigated to improve oxygen transfer at low agitation rates and thus reduce power consumption and shear stress on the microorganisms. The experiments were conducted at the 1-liter level and subsequently scaled-up to 50-liters using a constant volumetric oxygen transfer coefficient (&lt;i&gt;k&lt;sub&gt;L&lt;/sub&gt;a&lt;/i&gt;) method for scaling. In comparison to a conventional air-sparged fermentation, the MBD method considerably improved the cell mass yield, growth rate and power consumption in the 50-liter fermentor. Cell mass production in the MBD system at agitation rate of 150 rpm was about the same as those obtained for a conventional air-sparged system agitatid at 500 rpm. Power consumption in the conventional air-sparged system was three-fold that required for the same biomass yield in the MBD system. However, at the 1-liter scale, the MBD system did not show any significant advantage over the air-sparged system because of the high power consumption.","abstract_has_math":false,"creators":["Parakulsuksatid, Pramuk"],"institution":"Virginia Tech","degree_name":"Master of Science","degree_level":"masters","degree_discipline":"Biological Systems Engineering","degree_department":"Biological Systems Engineering","school":null,"contributors":[],"advisors":[],"committee_chairs":["Agblevor, Foster Aryi"],"committee_members":["Cundiff, John S.","Velander, William H.","Yousten, Allan A."],"year":2000,"date_issued":"2000-04-18","date_published":"2000-04-18","updated_at":"2026-07-22T22:20:17Z","subjects":["baker's yeast fermentation","pilot-scale","oxygen transfer","microbubble dispersion"],"languages":[],"rights":["In Copyright"],"rights_urls":["http://rightsstatements.org/vocab/InC/1.0/"],"identifier_entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05122000-00440044"],"render_values":[{"text":"etd-05122000-00440044","href":null,"code":true}]}]},"links":{"outbound_url":"http://hdl.handle.net/10919/32615","outbound_label":"Handle","outbound_source":"dc:identifier.uri"},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:contributor.committeechair","label":"Committee Chair","values":["Agblevor, Foster Aryi"]},{"key":"dc:contributor.committeemember","label":"Committee Member","values":["Cundiff, John S.","Velander, William H.","Yousten, Allan A."]},{"key":"dc:contributor.department","label":"Department","values":["Biological Systems Engineering"]},{"key":"dc:creator","label":"Author","values":["Parakulsuksatid, Pramuk"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.accessioned","label":"Dc Date Accessioned","values":["2014-03-14T20:36:24Z"]},{"key":"dc:date.available","label":"Dc Date Available","values":["2014-03-14T20:36:24Z","2001-05-12"]},{"key":"dc:date.issued","label":"Date","values":["2000-04-18"]},{"key":"dc:publisher","label":"Institution","values":["Virginia Tech"]},{"key":"dc:type","label":"Dc Type","values":["Thesis"]},{"key":"thesis:degree_discipline","label":"Discipline","values":["Biological Systems Engineering"]},{"key":"thesis:degree_level","label":"Degree Level","values":["masters"]},{"key":"thesis:degree_name","label":"Degree Name","values":["Master of Science"]},{"key":"thesis:institution_name","label":"Thesis Institution Name","values":["Virginia Polytechnic Institute and State University"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["baker's yeast fermentation","pilot-scale","oxygen transfer","microbubble dispersion"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["In Copyright"]},{"key":"dc:rights.uri","label":"Rights URI","values":["http://rightsstatements.org/vocab/InC/1.0/"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.other","label":"Dc Identifier Other","values":["etd-05122000-00440044"]},{"key":"dc:identifier.uri","label":"Identifier URI","values":["http://hdl.handle.net/10919/32615"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["In the large-scale production of <i>Saccharomyces cerevisiae</i> (baker's yeast), oxygen transfer, which is one of the major limiting factors, is improved by using high agitation rates. However, high agitation rates subject the microorganisms to high shear stress and caused high power consumption. A microbubble dispersion (MBD) method was investigated to improve oxygen transfer at low agitation rates and thus reduce power consumption and shear stress on the microorganisms. The experiments were conducted at the 1-liter level and subsequently scaled-up to 50-liters using a constant volumetric oxygen transfer coefficient (<i>k<sub>L</sub>a</i>) method for scaling. In comparison to a conventional air-sparged fermentation, the MBD method considerably improved the cell mass yield, growth rate and power consumption in the 50-liter fermentor. Cell mass production in the MBD system at agitation rate of 150 rpm was about the same as those obtained for a conventional air-sparged system agitatid at 500 rpm. Power consumption in the conventional air-sparged system was three-fold that required for the same biomass yield in the MBD system. However, at the 1-liter scale, the MBD system did not show any significant advantage over the air-sparged system because of the high power consumption."]},{"key":"dc:description.degree","label":"Dc Description Degree","values":["Master of Science"]},{"key":"dc:title","label":"Title","values":["Utilization of a Microbubble Dispersion to Increase Oxygen Transfer in Pilot-Scale Baker's Yeast Fermentation Unit"]}]}],"canonical_facts":{"dc:contributor.committeechair":["Agblevor, Foster Aryi"],"dc:contributor.committeemember":["Cundiff, John S.","Velander, William H.","Yousten, Allan A."],"dc:contributor.department":["Biological Systems Engineering"],"dc:creator":["Parakulsuksatid, Pramuk"],"dc:date.accessioned":["2014-03-14T20:36:24Z"],"dc:date.available":["2014-03-14T20:36:24Z","2001-05-12"],"dc:date.issued":["2000-04-18"],"dc:description.abstract":["In the large-scale production of <i>Saccharomyces cerevisiae</i> (baker's yeast), oxygen transfer, which is one of the major limiting factors, is improved by using high agitation rates. However, high agitation rates subject the microorganisms to high shear stress and caused high power consumption. A microbubble dispersion (MBD) method was investigated to improve oxygen transfer at low agitation rates and thus reduce power consumption and shear stress on the microorganisms. The experiments were conducted at the 1-liter level and subsequently scaled-up to 50-liters using a constant volumetric oxygen transfer coefficient (<i>k<sub>L</sub>a</i>) method for scaling. In comparison to a conventional air-sparged fermentation, the MBD method considerably improved the cell mass yield, growth rate and power consumption in the 50-liter fermentor. Cell mass production in the MBD system at agitation rate of 150 rpm was about the same as those obtained for a conventional air-sparged system agitatid at 500 rpm. Power consumption in the conventional air-sparged system was three-fold that required for the same biomass yield in the MBD system. However, at the 1-liter scale, the MBD system did not show any significant advantage over the air-sparged system because of the high power consumption."],"dc:description.degree":["Master of Science"],"dc:identifier.other":["etd-05122000-00440044"],"dc:identifier.uri":["http://hdl.handle.net/10919/32615"],"dc:publisher":["Virginia Tech"],"dc:rights":["In Copyright"],"dc:rights.uri":["http://rightsstatements.org/vocab/InC/1.0/"],"dc:subject":["baker's yeast fermentation","pilot-scale","oxygen transfer","microbubble dispersion"],"dc:title":["Utilization of a Microbubble Dispersion to Increase Oxygen Transfer in Pilot-Scale Baker's Yeast Fermentation Unit"],"dc:type":["Thesis"],"thesis:degree_discipline":["Biological Systems Engineering"],"thesis:degree_level":["masters"],"thesis:degree_name":["Master of Science"],"thesis:institution_name":["Virginia Polytechnic Institute and State University"]},"updated_at":"2026-07-22T22:20:17Z"}