{"id":{"repo_id":"wlv","oai_identifier":"oai:wlv.openrepository.com:2436/579925"},"canonical_url":"https://search.dev.ndltd.org/etd/wlv/oai:wlv.openrepository.com:2436/579925","repository":{"repo_id":"wlv","name":"University of Wolverhampton","base_url":"https://wlv.openrepository.com/server/oai/request"},"display":{"title":"Bacterial poly-gamma-Glutamic Acid (y-PGA) - a promising biosorbent of heavy metals","abstract":"Poly-γ-glutamic acid (γ-PGA) is a biopolymer made up of repeating units of L-glutamic acid, D-glutamic acid or both. γ-PGA is water soluble, non-toxic and biodegradable, and can be used safely in a variety of applications that are increasing rapidly. This study investigated the production of HMW γ-PGA by five Bacillus species (B. licheniformis 1525, B. licheniformis NCTC 6816, B. licheniformis ATCC 9945a, B. licheniformis ATCC 9945a and B. subtilis (natto) ATCC 15245) in GS, C and E media for the removal of heavy metals in wastewaters. The highest γ-PGA yields of 11.69 g/l and 11.59 g/l were produced by Bacillus subtilis (natto) ATCC 15245 in GS medium and medium C respectively. Upon characterization, γ- PGAs with different properties (crystallinity, acid/salt form and molecular weights ranging from 2.56 × 105 Da to 1.65 × 106 Da) were produced. The water soluble, non-toxic, HMW (Mw 1.65 × 106 Da) γ-PGA produced by B. subtilis (natto) ATCC 15245 in medium C was investigated as a sorbent for the removal of heavy metal ions including Cu2+, Zn2+, Ni2+, Cd2+ and Ag+. The results showed that the removal of metals by γ-PGA was more dependent on the concentration of γ-PGA than the solution pH. The highest metal ions removal of 93.50%, 88.13%, 90.21%, 90.56% and 86.34% by HMW γ-PGA were obtained for Cu2+, Zn2+, Ni2+, Cd2+ and Ag+ respectively. The presence of interfering metal ions could hinder the adsorption of individual metal ions by γ-PGA. The affinities of heavy metal ions for γ-PGA followed the order: Cu2+ > Zn2+ > Ni2+ > Cd2+. The effect of molecular weight of γ-PGA on metal removal was also investigated, and it was found that metal ion adsorption capacity of γ-PGA strongly depended on its molecular weight. The maximum amount (93.50%) of Cu2+ sorbed by HMW γ-PGA was higher compared to that (59.48%) sorbed by LMW γ-PGA. Isotherm models showed that the Redlich-Peterson best described the metal adsorption capacity of γ-PGA. It was also found that a multisite adsorption mechanism occurred via the complexation of metal ions with the free α-carboxyl and possibly the amide functional groups in γ-PGA.","abstract_html":"Poly-γ-glutamic acid (γ-PGA) is a biopolymer made up of repeating units of L-glutamic acid, D-glutamic acid or both. γ-PGA is water soluble, non-toxic and biodegradable, and can be used safely in a variety of applications that are increasing rapidly. This study investigated the production of HMW γ-PGA by five Bacillus species (B. licheniformis 1525, B. licheniformis NCTC 6816, B. licheniformis ATCC 9945a, B. licheniformis ATCC 9945a and B. subtilis (natto) ATCC 15245) in GS, C and E media for the removal of heavy metals in wastewaters. The highest γ-PGA yields of 11.69 g/l and 11.59 g/l were produced by Bacillus subtilis (natto) ATCC 15245 in GS medium and medium C respectively. Upon characterization, γ- PGAs with different properties (crystallinity, acid/salt form and molecular weights ranging from 2.56 × 105 Da to 1.65 × 106 Da) were produced. The water soluble, non-toxic, HMW (Mw 1.65 × 106 Da) γ-PGA produced by B. subtilis (natto) ATCC 15245 in medium C was investigated as a sorbent for the removal of heavy metal ions including Cu2+, Zn2+, Ni2+, Cd2+ and Ag+. The results showed that the removal of metals by γ-PGA was more dependent on the concentration of γ-PGA than the solution pH. The highest metal ions removal of 93.50%, 88.13%, 90.21%, 90.56% and 86.34% by HMW γ-PGA were obtained for Cu2+, Zn2+, Ni2+, Cd2+ and Ag+ respectively. The presence of interfering metal ions could hinder the adsorption of individual metal ions by γ-PGA. The affinities of heavy metal ions for γ-PGA followed the order: Cu2+ > Zn2+ > Ni2+ > Cd2+. The effect of molecular weight of γ-PGA on metal removal was also investigated, and it was found that metal ion adsorption capacity of γ-PGA strongly depended on its molecular weight. The maximum amount (93.50%) of Cu2+ sorbed by HMW γ-PGA was higher compared to that (59.48%) sorbed by LMW γ-PGA. Isotherm models showed that the Redlich-Peterson best described the metal adsorption capacity of γ-PGA. It was also found that a multisite adsorption mechanism occurred via the complexation of metal ions with the free α-carboxyl and possibly the amide functional groups in γ-PGA.","abstract_has_math":false,"creators":["Ogunleye, Adetoro"],"institution":null,"degree_name":null,"degree_level":null,"degree_discipline":null,"degree_department":null,"school":null,"contributors":[],"advisors":[],"committee_chairs":[],"committee_members":[],"year":2015,"date_issued":"2015-06","date_published":"2015-06","updated_at":"2026-07-24T06:10:28Z","subjects":["Poly-gamma-glutamic acid","Bacillus species","High molecular weight","Heavy metals","Metal ion adsorption","Isotherm models"],"languages":[],"rights":[],"rights_urls":["https://wlv.dspace7.openrepository.com/bitstreams/c327211d-6a2e-42d6-ae68-95107ea2ddb4/download"],"identifier_entries":[]},"links":{"outbound_url":null,"outbound_label":null,"outbound_source":null},"metadata_groups":[{"id":"people","label":"People","entries":[{"key":"dc:creator","label":"Author","values":["Ogunleye, Adetoro"]}]},{"id":"academic_context","label":"Academic Context","entries":[{"key":"dc:date.issued","label":"Date","values":["2015-06"]},{"key":"dc:relation.isreferencedby","label":"Dc Relation Isreferencedby","values":["http://hdl.handle.net/2436/579925"]},{"key":"dc:type","label":"Dc Type","values":["Thesis or dissertation"]}]},{"id":"subjects_keywords","label":"Subjects and Keywords","entries":[{"key":"dc:subject","label":"Dc Subject","values":["Poly-gamma-glutamic acid","Bacillus species","High molecular weight","Heavy metals","Metal ion adsorption","Isotherm models"]}]},{"id":"language_rights","label":"Language and Rights","entries":[{"key":"dc:rights","label":"Dc Rights","values":["https://wlv.dspace7.openrepository.com/bitstreams/c327211d-6a2e-42d6-ae68-95107ea2ddb4/download"]}]},{"id":"identifiers","label":"Identifiers","entries":[{"key":"dc:identifier.uri","label":"Identifier URI","values":["https://wlv.dspace7.openrepository.com/bitstreams/8fd0044f-7aee-4b5a-92de-5e1418a593e2/download"]}]},{"id":"additional","label":"Additional Metadata","entries":[{"key":"dc:description.abstract","label":"Abstract","values":["Poly-γ-glutamic acid (γ-PGA) is a biopolymer made up of repeating units of L-glutamic acid, D-glutamic acid or both. γ-PGA is water soluble, non-toxic and biodegradable, and can be used safely in a variety of applications that are increasing rapidly. This study investigated the production of HMW γ-PGA by five Bacillus species (B. licheniformis 1525, B. licheniformis NCTC 6816, B. licheniformis ATCC 9945a, B. licheniformis ATCC 9945a and B. subtilis (natto) ATCC 15245) in GS, C and E media for the removal of heavy metals in wastewaters. The highest γ-PGA yields of 11.69 g/l and 11.59 g/l were produced by Bacillus subtilis (natto) ATCC 15245 in GS medium and medium C respectively. Upon characterization, γ- PGAs with different properties (crystallinity, acid/salt form and molecular weights ranging from 2.56 × 105 Da to 1.65 × 106 Da) were produced. The water soluble, non-toxic, HMW (Mw 1.65 × 106 Da) γ-PGA produced by B. subtilis (natto) ATCC 15245 in medium C was investigated as a sorbent for the removal of heavy metal ions including Cu2+, Zn2+, Ni2+, Cd2+ and Ag+. The results showed that the removal of metals by γ-PGA was more dependent on the concentration of γ-PGA than the solution pH. The highest metal ions removal of 93.50%, 88.13%, 90.21%, 90.56% and 86.34% by HMW γ-PGA were obtained for Cu2+, Zn2+, Ni2+, Cd2+ and Ag+ respectively. The presence of interfering metal ions could hinder the adsorption of individual metal ions by γ-PGA. The affinities of heavy metal ions for γ-PGA followed the order: Cu2+ > Zn2+ > Ni2+ > Cd2+. The effect of molecular weight of γ-PGA on metal removal was also investigated, and it was found that metal ion adsorption capacity of γ-PGA strongly depended on its molecular weight. The maximum amount (93.50%) of Cu2+ sorbed by HMW γ-PGA was higher compared to that (59.48%) sorbed by LMW γ-PGA. Isotherm models showed that the Redlich-Peterson best described the metal adsorption capacity of γ-PGA. It was also found that a multisite adsorption mechanism occurred via the complexation of metal ions with the free α-carboxyl and possibly the amide functional groups in γ-PGA."]},{"key":"dc:format.checksum.md5","label":"Dc Format Checksum Md5","values":["e87405b506864d51990351bd1501276f","5517315717c40b6a24a89eefbb68951b","fec251d14fec12fdcf715d7a9e87c447"]},{"key":"dc:title","label":"Title","values":["Bacterial poly-gamma-Glutamic Acid (y-PGA) - a promising biosorbent of heavy metals"]}]}],"canonical_facts":{"dc:creator":["Ogunleye, Adetoro"],"dc:date.issued":["2015-06"],"dc:description.abstract":["Poly-γ-glutamic acid (γ-PGA) is a biopolymer made up of repeating units of L-glutamic acid, D-glutamic acid or both. γ-PGA is water soluble, non-toxic and biodegradable, and can be used safely in a variety of applications that are increasing rapidly. This study investigated the production of HMW γ-PGA by five Bacillus species (B. licheniformis 1525, B. licheniformis NCTC 6816, B. licheniformis ATCC 9945a, B. licheniformis ATCC 9945a and B. subtilis (natto) ATCC 15245) in GS, C and E media for the removal of heavy metals in wastewaters. The highest γ-PGA yields of 11.69 g/l and 11.59 g/l were produced by Bacillus subtilis (natto) ATCC 15245 in GS medium and medium C respectively. Upon characterization, γ- PGAs with different properties (crystallinity, acid/salt form and molecular weights ranging from 2.56 × 105 Da to 1.65 × 106 Da) were produced. The water soluble, non-toxic, HMW (Mw 1.65 × 106 Da) γ-PGA produced by B. subtilis (natto) ATCC 15245 in medium C was investigated as a sorbent for the removal of heavy metal ions including Cu2+, Zn2+, Ni2+, Cd2+ and Ag+. The results showed that the removal of metals by γ-PGA was more dependent on the concentration of γ-PGA than the solution pH. The highest metal ions removal of 93.50%, 88.13%, 90.21%, 90.56% and 86.34% by HMW γ-PGA were obtained for Cu2+, Zn2+, Ni2+, Cd2+ and Ag+ respectively. The presence of interfering metal ions could hinder the adsorption of individual metal ions by γ-PGA. The affinities of heavy metal ions for γ-PGA followed the order: Cu2+ > Zn2+ > Ni2+ > Cd2+. The effect of molecular weight of γ-PGA on metal removal was also investigated, and it was found that metal ion adsorption capacity of γ-PGA strongly depended on its molecular weight. The maximum amount (93.50%) of Cu2+ sorbed by HMW γ-PGA was higher compared to that (59.48%) sorbed by LMW γ-PGA. Isotherm models showed that the Redlich-Peterson best described the metal adsorption capacity of γ-PGA. 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