{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,18]],"date-time":"2026-09-18T10:52:39Z","timestamp":1789728759956,"version":"4.0.1"},"reference-count":35,"publisher":"American Society for Microbiology","issue":"8","license":[{"start":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T00:00:00Z","timestamp":1785801600000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"},{"start":{"date-parts":[[2026,8,4]],"date-time":"2026-08-04T00:00:00Z","timestamp":1785801600000},"content-version":"tdm","delay-in-days":0,"URL":"https:\/\/journals.asm.org\/non-commercial-tdm-license"}],"funder":[{"DOI":"10.13039\/100007802","name":"Institute for Fermentation, Osaka","doi-asserted-by":"publisher","award":["LA-2022-012"],"award-info":[{"award-number":["LA-2022-012"]}],"id":[{"id":"10.13039\/100007802","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Grant in Aid for Scientific Research (B)","award":["25K03298"],"award-info":[{"award-number":["25K03298"]}]},{"name":"Miyoshi Oil &amp; Fat Co., Ltd."}],"content-domain":{"domain":["journals.asm.org"],"crossmark-restriction":true},"short-container-title":["Microbiol Spectr"],"published-print":{"date-parts":[[2026,8,4]]},"abstract":"<jats:title>ABSTRACT<\/jats:title>\n                  <jats:sec>\n                    <jats:title\/>\n                    <jats:p>\n                      In the oleochemical industry, a fat-splitting process is used to generate a methanol-free byproduct, oleochemical industrial waste, that includes crude glycerol. The oleaginous yeast\n                      <jats:italic toggle=\"yes\">Rhodotorula toruloides<\/jats:italic>\n                      is a nonconventional yeast that is well known for its industrial potential as a producer of lipids, carotenoids, and enzymes. Extracellular polysaccharides (EPSs) are of increasing interest due to their many applications. In this study, we found that\n                      <jats:italic toggle=\"yes\">R. toruloides<\/jats:italic>\n                      NBRC 8766 strain produced mannose-rich and high-molecular-weight EPSs with a mannose content (mol%) exceeding 90% and an estimated molecular weight greater than 10,000 k from oleochemical industrial waste crude glycerol or pure glycerol. Components in the industrial waste increased EPS production. The concentration of NH\n                      <jats:sub>4<\/jats:sub>\n                      <jats:sup>+<\/jats:sup>\n                      ions in the culture medium was identified as a key factor in discriminating the cells producing the EPS (EPS-producing cells) from EPS-nonproducing cells. Further investigations demonstrated that a sufficient concentration of NH\n                      <jats:sub>4<\/jats:sub>\n                      <jats:sup>+<\/jats:sup>\n                      ions (38 mM or more) to acidify the medium to a pH of 2.0 or lower is key to EPS production under these conditions. Therefore, it was hypothesized that the\n                      <jats:italic toggle=\"yes\">R. toruloides<\/jats:italic>\n                      NBRC 8766 strain would produce EPS in response to extracellular acidity. Fluorescent and transmission electron microscopic analyses of the two cell types revealed differences; the EPS-producing cells had immature lipid droplets and marked two-layered cell walls, where the outer layer was darker and looked like it was wearing \u201cfuzz,\u201d which was assumed to be the EPSs released from the cells. The EPS-nonproducing cells had clear lipid droplets, one-layered cell walls, and more abundant intracellular polysaccharide granules.\n                    <\/jats:p>\n                  <\/jats:sec>\n                  <jats:sec>\n                    <jats:title>IMPORTANCE<\/jats:title>\n                    <jats:p>\n                      In this study, we demonstrated that oleochemical industrial waste is a promising source of crude glycerol for EPS production and that\n                      <jats:italic toggle=\"yes\">R. toruloides<\/jats:italic>\n                      is a promising producer of not only lipids but also EPSs from glycerol. Moreover, the identification of the concentration of NH\n                      <jats:sub>4<\/jats:sub>\n                      <jats:sup>+<\/jats:sup>\n                      ions in the culture medium enabled the discrimination of EPS-producing cells from EPS-nonproducing cells. The presence of sufficient NH\n                      <jats:sub>4<\/jats:sub>\n                      <jats:sup>+<\/jats:sup>\n                      ions to acidify the medium was demonstrated to be key to EPS production in these conditions. This suggests that the\n                      <jats:italic toggle=\"yes\">R. toruloides<\/jats:italic>\n                      NBRC 8766 strain produces EPS in response to extracellular acidity. The morphological observations of the EPS-producing and EPS-nonproducing cells provide a further basis for understanding the molecular mechanism underlying the production of mannose-rich and high-molecular weight-EPS, as well as clues for artificially increasing the amounts of EPSs and lipids produced.\n                    <\/jats:p>\n                  <\/jats:sec>","DOI":"10.1128\/spectrum.00429-26","type":"journal-article","created":{"date-parts":[[2026,6,29]],"date-time":"2026-06-29T13:01:41Z","timestamp":1782738101000},"update-policy":"https:\/\/doi.org\/10.1128\/asmj-crossmark-policy-page","source":"Crossref","is-referenced-by-count":1,"title":["Ammonium ion concentration-dependent production of extracellular polysaccharides from glycerol by an oleaginous yeast: visualization of the producer cells"],"prefix":"10.1128","volume":"14","author":[{"given":"Soyoka","family":"Takegawa","sequence":"first","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00b45dj41","id-type":"ROR","asserted-by":"publisher"}],"name":"Department of Environmental Science, Faculty of Bioresources and Environmental Sciences, Ishikawa Prefectural University","place":["Nonoichi, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-6035-0481","authenticated-orcid":true,"given":"Chiaki","family":"Matsuzaki","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00b45dj41","id-type":"ROR","asserted-by":"publisher"}],"name":"Laboratory for Environmental Biotechnology, Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University","place":["Nonoichi, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Taiki","family":"Hikosaka","sequence":"additional","affiliation":[{"name":"Miyoshi Oil & Fat Co., Ltd.","place":["Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuji","family":"Okabe","sequence":"additional","affiliation":[{"name":"Miyoshi Oil & Fat Co., Ltd.","place":["Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Koji","family":"Kawai","sequence":"additional","affiliation":[{"name":"Miyoshi Oil & Fat Co., Ltd.","place":["Tokyo, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-3640-9540","authenticated-orcid":true,"given":"Shigeyuki","family":"Kawai","sequence":"additional","affiliation":[{"id":[{"id":"https:\/\/ror.org\/00b45dj41","id-type":"ROR","asserted-by":"publisher"}],"name":"Laboratory for Environmental Biotechnology, Research Institute for Bioresources and Biotechnology, Ishikawa Prefectural University","place":["Nonoichi, Japan"]}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"235","reference":[{"key":"e_1_3_4_2_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijbiomac.2024.129536"},{"key":"e_1_3_4_3_2","doi-asserted-by":"publisher","DOI":"10.1186\/s12934-024-02336-x"},{"key":"e_1_3_4_4_2","doi-asserted-by":"publisher","DOI":"10.1002\/yea.3838"},{"key":"e_1_3_4_5_2","doi-asserted-by":"publisher","DOI":"10.1007\/s43393-021-00036-w"},{"key":"e_1_3_4_6_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.biortech.2019.122155"},{"key":"e_1_3_4_7_2","doi-asserted-by":"publisher","DOI":"10.1080\/10826068.2011.577883"},{"key":"e_1_3_4_8_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ijbiomac.2025.139917"},{"key":"e_1_3_4_9_2","doi-asserted-by":"publisher","DOI":"10.1007\/s12223-021-00856-2"},{"key":"e_1_3_4_10_2","doi-asserted-by":"publisher","DOI":"10.1016\/j.ejbt.2016.02.008"},{"key":"e_1_3_4_11_2","doi-asserted-by":"publisher","DOI":"10.1186\/s12934-021-01712-1"},{"key":"e_1_3_4_12_2","doi-asserted-by":"publisher","DOI":"10.1021\/acs.jafc.2c07361"},{"key":"e_1_3_4_13_2","doi-asserted-by":"publisher","DOI":"10.1186\/s12934-016-0467-x"},{"key":"e_1_3_4_14_2","doi-asserted-by":"publisher","DOI":"10.3390\/jof9111073"},{"key":"e_1_3_4_15_2","doi-asserted-by":"publisher","DOI":"10.1128\/aem.00947-25"},{"key":"e_1_3_4_16_2","doi-asserted-by":"publisher","DOI":"10.1002\/fsn3.1792"},{"key":"e_1_3_4_17_2","first-page":"2151","article-title":"Deproteinization in purification of exopolysaccharide from Ophiocordyceps sinensis olive oil-stimulated culture","volume":"14","author":"Thuy H","year":"2018","unstructured":"Thuy H, Bao C, Phuong T, Lap D, Hai N, Minh H, Tien T. 2018. 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