{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,3]],"date-time":"2026-09-03T15:12:59Z","timestamp":1788448379877,"version":"build-2803163510"},"reference-count":49,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2022,8,17]],"date-time":"2022-08-17T00:00:00Z","timestamp":1660694400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/501100001809","name":"National Natural Science Foundation of China","doi-asserted-by":"publisher","award":["31700071"],"award-info":[{"award-number":["31700071"]}],"id":[{"id":"10.13039\/501100001809","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Microbiol."],"abstract":"<jats:p>Silkworm excrement is hard to be degraded or bio-utilized by environmental microorganisms due to its high content of heavy metals and antimicrobial biomacromolecules in mulberry leaves. In traditional Chinese silk industry, the silkworm excrement results in environmental problems. In this study, the silkworm excrement after chlorophyll ethanol-extraction was researched. An open fermentation strategy was developed using the silkworm excrement as the sole or partial carbon source by haloarchaea to accumulate polyhydroxyalkanoates. As a haloarchaeon with strong carbon source utilization ability, <jats:italic>Haloferax mediterranei<\/jats:italic> was found to accumulate a certain amount of poly(3-hydroxybutyrate-<jats:italic>co<\/jats:italic>-3-hydroxyvalerate; PHBV) using waste silkworm excrement. The results showed that the addition of silkworm excrement into glucose based fermentation medium can significantly improve the production of PHBV. Using a mixture carbon source including the extract of silkworm excrement and glucose (with a 1:1 carbon content ratio), the yield of PHBV was 1.73\u2009\u00b1\u20090.12\u2009g\/l, which showed a 26% increase than that of fermentation without the silkworm excrement addition. When the NaCl content of medium was set to approximately 15%, fermentation without sterilization was performed using silkworm excrement as the carbon source. Moreover, the addition of the silkworm excrement extract could increase the 3-hydroxyvalerate (3\u2009HV) content of PHBV regardless of the sterilization or non-sterilization fermentation conditions. When using silkworm excrement as the sole carbon source, the 3\u2009HV content was as high as 16.37\u2009\u00b1\u20090.54\u2009mol %. The real-time quantitative PCR results showed that the addition of the silkworm excrement could specifically enhance the expression of genes involved in the aspartate\/2-ketobutyric acid pathway related to 3\u2009HV synthesis in <jats:italic>H. mediterranei<\/jats:italic>, and further analysis of the amino acid of the silkworm excrement suggested that the high content of threonine in the silkworm excrement might be the reason for the increase of 3\u2009HV content. Taken together, the success of non-sterile fermentation in hypersaline condition using haloarchaea implied a novel way to reuse the silkworm excrement, which not only reduces the production costs of PHBV, but also is conducive to environmental protection.<\/jats:p>","DOI":"10.3389\/fmicb.2022.981605","type":"journal-article","created":{"date-parts":[[2022,8,17]],"date-time":"2022-08-17T07:10:16Z","timestamp":1660720216000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":18,"title":["Study on the production of high 3HV content PHBV via an open fermentation with waste silkworm excrement as the carbon source by the haloarchaeon Haloferax mediterranei"],"prefix":"10.3389","volume":"13","author":[{"given":"Shuangfeng","family":"Cai","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yaran","family":"Wu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Runjie","family":"Liu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hongzhe","family":"Jia","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yunxiao","family":"Qiu","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Min","family":"Jiang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yuwen","family":"Ma","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xingxu","family":"Yang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Siyu","family":"Zhang","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Yan","family":"Zhao","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Lei","family":"Cai","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1965","published-online":{"date-parts":[[2022,8,17]]},"reference":[{"key":"ref1","doi-asserted-by":"publisher","first-page":"615","DOI":"10.1016\/j.ijbiomac.2017.09.026","article-title":"Perspectives on the production, structural characteristics and potential applications of bioplastics derived from polyhydroxyalkanoates","volume":"107","author":"Albuquerque","year":"2018","journal-title":"Int. J. Biol. Macromol."},{"key":"ref2","doi-asserted-by":"publisher","first-page":"47","DOI":"10.1016\/j.nbt.2016.05.003","article-title":"A one-stage cultivation process for the production of poly-3-(hydroxybutyrate-co-hydroxyvalerate) from olive mill wastewater by Haloferax mediterranei","volume":"34","author":"Alsafadi","year":"2017","journal-title":"New Biotechnol."},{"key":"ref3","doi-asserted-by":"publisher","first-page":"280","DOI":"10.1111\/j.1574-6968.1992.tb05850.x","article-title":"Physical properties of poly(hydroxybutyrate) and copolymers of hydroxybutyrate and hydroxyvalerate","volume":"103","author":"Barham","year":"1992","journal-title":"FEMS Microbiol. Lett."},{"key":"ref4","doi-asserted-by":"publisher","first-page":"182","DOI":"10.1111\/lam.12762","article-title":"Chicken feather hydrolysate as an inexpensive complex nitrogen source for PHA production by Cupriavidus necator on waste frying oils","volume":"65","author":"Benesova","year":"2017","journal-title":"Lett. Appl. Microbiol."},{"key":"ref5","doi-asserted-by":"publisher","first-page":"717","DOI":"10.1007\/s11274-015-1823-4","article-title":"Integration of poly-3-(hydroxybutyrate-co-hydroxyvalerate) production by Haloferax mediterranei through utilization of stillage from rice-based ethanol manufacture in India and its techno-economic analysis","volume":"31","author":"Bhattacharyya","year":"2015","journal-title":"World J. Microbiol. Biotechnol."},{"key":"ref6","doi-asserted-by":"publisher","first-page":"34","DOI":"10.1186\/2191-0855-2-34","article-title":"Utilization of vinasse for production of poly-3-(hydroxybutyrate-co-hydroxyvalerate) by Haloferax mediterranei","volume":"2","author":"Bhattacharyya","year":"2012","journal-title":"AMB Express"},{"key":"ref7","doi-asserted-by":"publisher","first-page":"463","DOI":"10.1007\/s00792-013-0622-9","article-title":"Production of poly-3-(hydroxybutyrate-co-hydroxyvalerate) by Haloferax mediterranei using rice-based ethanol stillage with simultaneous recovery and re-use of medium salts","volume":"18","author":"Bhattacharyya","year":"2014","journal-title":"Extremophiles"},{"key":"ref8","doi-asserted-by":"publisher","first-page":"1946","DOI":"10.1128\/AEM.07114-11","article-title":"Identification of the haloarchaeal phasin (PhaP) That functions in polyhydroxyalkanoate accumulation and granule formation in Haloferax mediterranei","volume":"78","author":"Cai","year":"2012","journal-title":"Appl. Environ. Microbiol."},{"key":"ref9","doi-asserted-by":"publisher","first-page":"373","DOI":"10.1128\/AEM.02878-14","article-title":"A novel DNA-binding protein, PhaR, plays a central role in the regulation of polyhydroxyalkanoate accumulation and granule formation in the haloarchaeon Haloferax mediterranei","volume":"81","author":"Cai","year":"2015","journal-title":"Appl. Environ. Microbiol."},{"key":"ref10","doi-asserted-by":"publisher","first-page":"1430","DOI":"10.1128\/AEM.03372-13","article-title":"Analysis of the transcriptional regulator GlpR, promoter elements, and posttranscriptional processing involved in fructose-induced activation of the phosphoenolpyruvate-dependent sugar phosphotransferase system in Haloferax mediterranei","volume":"80","author":"Cai","year":"2014","journal-title":"Appl. Environ. Microbiol."},{"key":"ref11","doi-asserted-by":"publisher","first-page":"7122","DOI":"10.3390\/molecules26237122","article-title":"Production of polyhydroxyalkanoates in unsterilized hyper-saline medium by halophiles using waste silkworm excrement as carbon source","volume":"26","author":"Cai","year":"2021","journal-title":"Molecules"},{"key":"ref12","doi-asserted-by":"publisher","first-page":"391","DOI":"10.1016\/j.biortech.2012.01.176","article-title":"Effect of cultivation parameters on the production of poly(3-hydroxybutyrate-co-4-hydroxybutyrate) and poly(3-hydroxybutyrate-4-hydroxybutyrate-3-hydroxyvalerate) by Cupriavidus necator using waste glycerol","volume":"111","author":"Cavalheiro","year":"2012","journal-title":"Bioresour. Technol."},{"key":"ref13","doi-asserted-by":"publisher","first-page":"621","DOI":"10.1016\/j.jbiosc.2010.07.014","article-title":"Current trends in biodegradable polyhydroxyalkanoates","volume":"110","author":"Chanprateep","year":"2010","journal-title":"J. Biosci. Bioeng."},{"key":"ref14","doi-asserted-by":"publisher","first-page":"548","DOI":"10.1128\/jb.179.2.548-551.1997","article-title":"Isolation, sequence, and expression of the gene encoding halocin H4, a bacteriocin from the halophilic archaeon Haloferax mediterranei R4","volume":"179","author":"Cheung","year":"1997","journal-title":"J. Bacteriol."},{"key":"ref15","doi-asserted-by":"crossref","first-page":"335","DOI":"10.1007\/s004490050394","article-title":"Process analysis and economic evaluation for poly(3-hydroxybutyrate) production by fermentation","volume":"17","author":"Choi","year":"1997","journal-title":"Bioprocess Biosyst. Eng."},{"key":"ref16","doi-asserted-by":"publisher","first-page":"13","DOI":"10.1007\/s002530051357","article-title":"Factors affecting tile economics of poly-hydroxyalkanoate production by bacterial fermentation","volume":"51","author":"Choi","year":"1999","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref17","doi-asserted-by":"publisher","first-page":"5511","DOI":"10.1021\/es011110o","article-title":"Green technology for conversion of food scraps to biodegradable thermoplastic polyhydroxyalkanoates","volume":"36","author":"Du","year":"2002","journal-title":"Environ. Sci. Technol."},{"key":"ref18","doi-asserted-by":"publisher","first-page":"413","DOI":"10.1016\/S0959-6526(99)00159-6","article-title":"Upgrading of organic waste: production of the copolymer poly-3-hydroxybutyrate-co-valerate by Ralstonia eutrophus with organic waste as sole carbon source","volume":"7","author":"Ganzeveld","year":"1999","journal-title":"J. Clean. Prod."},{"key":"ref20","doi-asserted-by":"publisher","first-page":"2922","DOI":"10.1128\/AEM.03915-12","article-title":"Multiple propionyl coenzyme A-supplying pathways for production of the bioplastic poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in Haloferax mediterranei","volume":"79","author":"Han","year":"","journal-title":"Appl. Environ. Microbiol."},{"key":"ref21","doi-asserted-by":"publisher","first-page":"6058","DOI":"10.1128\/AEM.00953-07","article-title":"Molecular characterization of the phaECHm genes, required for biosynthesis of poly(3-hydroxybutyrate) in the extremely halophilic archaeon Haloarcula marismortui","volume":"73","author":"Han","year":"2007","journal-title":"Appl. Environ. Microbiol."},{"key":"ref22","doi-asserted-by":"publisher","first-page":"51","DOI":"10.1016\/j.seppur.2013.04.047","article-title":"Simultaneous aqueous two-phase extraction and saponification reaction of chlorophyll from silkworm excrement","volume":"115","author":"Han","year":"","journal-title":"Sep. Purif. Technol."},{"key":"ref23","doi-asserted-by":"publisher","first-page":"578","DOI":"10.1021\/bm5016267","article-title":"Biosynthesis, characterization, and hemostasis potential of tailor-made poly(3-hydroxybutyrate-co-3-hydroxyvalerate) produced by Haloferax mediterranei","volume":"16","author":"Han","year":"2015","journal-title":"Biomacromolecules"},{"key":"ref24","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1155\/2013\/129268","article-title":"Archaeal production of polyhydroxyalkanoate (PHA) co-and terpolyesters from biodiesel industry-derived by-products","volume":"2013","author":"Hermann-Krauss","year":"2013","journal-title":"Archaea"},{"key":"ref25","doi-asserted-by":"publisher","first-page":"319","DOI":"10.1007\/s002530000394","article-title":"Polymer production by two newly isolated extremely halophilic archaea: application of a novel corrosion-resistant bioreactor","volume":"54","author":"Hezayen","year":"2000","journal-title":"Appl. Microbiol. Biotechnol."},{"key":"ref26","doi-asserted-by":"publisher","first-page":"5104","DOI":"10.1128\/AEM.01370-13","article-title":"Haloarchaeal-type beta-ketothiolases involved in poly(3-hydroxybutyrate-co-3-hydroxyvalerate) synthesis in Haloferax mediterranei","volume":"79","author":"Hou","year":"2013","journal-title":"Appl. Environ. Microbiol."},{"key":"ref27","doi-asserted-by":"publisher","first-page":"794","DOI":"10.1128\/AEM.03167-14","article-title":"Propionyl coenzyme A (propionyl-CoA) carboxylase in Haloferax mediterranei: indispensability for propionyl-CoA assimilation and impacts on global metabolism","volume":"81","author":"Hou","year":"2015","journal-title":"Appl. Environ. Microbiol."},{"key":"ref28","doi-asserted-by":"publisher","first-page":"102785","DOI":"10.1016\/j.est.2021.102785","article-title":"Using silkworm excrement and spent lead paste to prepare additives for improving the cycle life of lead-acid batteries","volume":"41","author":"Hu","year":"2021","journal-title":"J. Energy Storage"},{"key":"ref29","doi-asserted-by":"publisher","first-page":"125179","DOI":"10.1016\/j.chemosphere.2019.125179","article-title":"The mobility of cadmium and lead in the soil-mulberry-silkworm system","volume":"242","author":"Jiang","year":"2020","journal-title":"Chemosphere"},{"key":"ref30","doi-asserted-by":"publisher","first-page":"e2748","DOI":"10.21769\/BioProtoc.2748","article-title":"Determination of polyhydroxybutyrate (PHB) content in Ralstonia eutropha using gas chromatography and nile red staining","volume":"8","author":"Juengert","year":"2018","journal-title":"Bio Protoc."},{"key":"ref31","doi-asserted-by":"publisher","first-page":"175","DOI":"10.1271\/bbb.90459","article-title":"Poly(3-hydroxybutyrate) production by isolated Halomonas sp. KM-1 using waste glycerol","volume":"74","author":"Kawata","year":"2010","journal-title":"Biosci. Biotechnol. Biochem."},{"key":"ref32","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1002\/(SICI)1097-0290(19960105)49:1<1::AID-BIT1>3.0.CO;2-P","article-title":"Bacterial polyhydroxyalkanoates","volume":"49","author":"Lee","year":"1996","journal-title":"Biotechnol. Bioeng."},{"key":"ref33","doi-asserted-by":"publisher","first-page":"1007","DOI":"10.1038\/s42003-021-02541-z","article-title":"Optimising PHBV biopolymer production in haloarchaea via CRISPRi-mediated redirection of carbon flux","volume":"4","author":"Lin","year":"2021","journal-title":"Commun. Biol."},{"key":"ref34","doi-asserted-by":"publisher","first-page":"1300","DOI":"10.1021\/pr300969m","article-title":"Proteome reference map of Haloarcula hispanica and comparative proteomic and transcriptomic analysis of polyhydroxyalkanoate biosynthesis under genetic and environmental perturbations","volume":"12","author":"Liu","year":"","journal-title":"J. Proteome Res."},{"key":"ref35","doi-asserted-by":"publisher","first-page":"441","DOI":"10.1016\/j.jgg.2013.04.009","article-title":"Genome-wide analysis of gene expression in stationary phase and genetic characterization of stationary-phase-dependent halocin gene expression in the haloarchaeon Haloferax mediterranei","volume":"40","author":"Liu","year":"","journal-title":"J. Genet. Genomics"},{"key":"ref36","doi-asserted-by":"publisher","first-page":"4173","DOI":"10.1128\/JB.00134-08","article-title":"Genetic and biochemical characterization of the poly(3-hydroxybutyrate-co-3-hydroxyvalerate) synthase in Haloferax mediterranei","volume":"190","author":"Lu","year":"2008","journal-title":"J. Bacteriol."},{"key":"ref37","doi-asserted-by":"publisher","first-page":"e4780","DOI":"10.7717\/peerj.4780","article-title":"Screening of polyhydroxyalkanoate-producing bacteria and PhaC-encoding genes in two hypersaline microbial mats from Guerrero Negro, Baja California Sur, Mexico","volume":"6","author":"Mart\u00ednez-Guti\u00e9rrez","year":"2018","journal-title":"PeerJ"},{"key":"ref38","doi-asserted-by":"publisher","first-page":"977","DOI":"10.1002\/jobm.201800279","article-title":"Production and recovery of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) from biodiesel liquid waste (BLW)","volume":"58","author":"Martla","year":"2018","journal-title":"J. Basic Microbiol."},{"key":"ref39","doi-asserted-by":"publisher","first-page":"7244","DOI":"10.3390\/molecules26237244","article-title":"Current advances towards 4-hydroxybutyrate containing polyhydroxyalkanoates production for biomedical applications","volume":"26","author":"Mitra","year":"2021","journal-title":"Molecules"},{"key":"ref40","doi-asserted-by":"publisher","first-page":"86","DOI":"10.1186\/s12934-020-01342-z","article-title":"Current developments on polyhydroxyalkanoates synthesis by using halophiles as a promising cell factory","volume":"19","author":"Mitra","year":"2020","journal-title":"Microb. Cell Fact."},{"key":"ref41","doi-asserted-by":"publisher","first-page":"2634","DOI":"10.1016\/j.wasman.2014.09.007","article-title":"Use of residual banana for polyhydroxybutyrate (PHB) production: case of study in an integrated biorefinery","volume":"34","author":"Naranjo","year":"2014","journal-title":"Waste Manag."},{"key":"ref42","doi-asserted-by":"publisher","first-page":"533","DOI":"10.1007\/s12272-011-0403-x","article-title":"Isolation of megastigmane sesquiterpenes from the silkworm (Bombyx mori L.) droppings and their promotion activity on HO-1 and SIRT1","volume":"34","author":"Park","year":"2011","journal-title":"Arch. Pharm. Res."},{"key":"ref43","doi-asserted-by":"publisher","first-page":"479","DOI":"10.1007\/s11157-021-09575-z","article-title":"Improving biological production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) co-polymer: a critical review","volume":"20","author":"Policastro","year":"2021","journal-title":"Rev. Environ. Sci. Biotechnol."},{"key":"ref44","doi-asserted-by":"publisher","first-page":"1347","DOI":"10.1111\/jam.12135","article-title":"Characterization of polyhydroxyalkanoates accumulated by a moderately halophilic salt pan isolate Bacillus megaterium strain H16","volume":"114","author":"Salgaonkar","year":"2013","journal-title":"J. Appl. Microbiol."},{"key":"ref45","doi-asserted-by":"publisher","first-page":"34","DOI":"10.1016\/j.ymben.2014.09.001","article-title":"Engineering Halomonas TD01 for the low-cost production of polyhydroxyalkanoates","volume":"26","author":"Tan","year":"2014","journal-title":"Metab. Eng."},{"key":"ref46","doi-asserted-by":"publisher","first-page":"8130","DOI":"10.1016\/j.biortech.2011.05.068","article-title":"Unsterile and continuous production of polyhydroxybutyrate by Halomonas TD01","volume":"102","author":"Tan","year":"2011","journal-title":"Bioresour. Technol."},{"key":"ref47","doi-asserted-by":"publisher","first-page":"338","DOI":"10.4014\/jmb.2008.08057","article-title":"Production of polyhydroxyalkanoates (PHA) by Haloferax mediterranei from food waste derived nutrients for biodegradable plastic applications","volume":"31","author":"Wang","year":"2020","journal-title":"J. Microbiol. Biotechnol."},{"key":"ref48","doi-asserted-by":"publisher","first-page":"3525","DOI":"10.14233\/ajchem.2013.13815","article-title":"Evaluation of amino acid and vitamin B2 and E composition of genetically modified Antidwarf mosaic maize by automatic amino acid analyzer and HPLC","volume":"25","author":"Yan","year":"2013","journal-title":"Asian J. Chem."},{"key":"ref49","doi-asserted-by":"publisher","first-page":"1","DOI":"10.1186\/1754-6834-7-108","article-title":"A seawater-based open and continuous process for polyhydroxyalkanoates production by recombinant Halomonas campaniensis LS21 grown in mixed substrates","volume":"7","author":"Yue","year":"2014","journal-title":"Biotechnol. Biofuels"},{"key":"ref50","doi-asserted-by":"publisher","first-page":"3027","DOI":"10.1007\/s00253-012-4415-3","article-title":"Improving polyhydroxyalkanoate production by knocking out the genes involved in exopolysaccharide biosynthesis in Haloferax mediterranei","volume":"97","author":"Zhao","year":"2013","journal-title":"Appl. Microbiol. Biotechnol."}],"container-title":["Frontiers in Microbiology"],"original-title":[],"link":[{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2022.981605\/full","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,8,17]],"date-time":"2022-08-17T07:10:20Z","timestamp":1660720220000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.frontiersin.org\/articles\/10.3389\/fmicb.2022.981605\/full"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2022,8,17]]},"references-count":49,"alternative-id":["10.3389\/fmicb.2022.981605"],"URL":"https:\/\/doi.org\/10.3389\/fmicb.2022.981605","relation":{},"ISSN":["1664-302X"],"issn-type":[{"value":"1664-302X","type":"electronic"}],"subject":[],"published":{"date-parts":[[2022,8,17]]},"article-number":"981605"}}