Polyester production by halophilic and halotolerant bacterial strains obtained from mangrove soil samples located in Northern Vietnam

The research article "Polyester production by halophilic and halotolerant bacterial strains obtained from mangrove soil samples located in Northern Vietnam" reports halophilic and halotolerant bacteria isolated from mangrove forests located in Northern Vietnam. Several of these bacteria were able to synthesize polyhydroxyalkanoates (PHAs). PHAs are polyesters stored by microorganisms under the presence of considerable amounts of a carbon source and deficiency of other essential nutrient such as nitrogen or phosphorous. Mangrove forests in Northern Vietnam are saline coastal habitats that have not been microbiologically studied. Mangrove ecosystems are, in general, rich in organic matter, but deficient in nutrients such as nitrogen and phosphorus.
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Polyester production by halophilic and halotolerant bacterial strains obtained from mangrove soil samples located in Northern VietnamPolyester production by halophilic and halotolerantbacterial strains obtained from mangrove soil sampleslocated in Northern VietnamDoan Van-Thuoc1, Tran Huu-Phong1, Nguyen Thi-Binh1, Nguyen Thi-Tho1, Duong Minh-Lam1 &Jorge Quillaguama´n21 Department of Microbiology and Biotechnology, Faculty of Biology, Hanoi National University of Education, 136 Xuan Thuy, Cau Giay, Hanoi,Vietnam2 Center of Biotechnology, Faculty of Sciences and Technology, Universidad Mayor de San Simo´n, Cochabamba, BoliviaKeywords AbstractBiopolyesters, halophilic bacteria, halotolerantbacteria, mangrove forests, This research article reports halophilic and halotolerant bacteria isolated frompolyhydroxyalkanoates mangrove forests located in Northern Vietnam. Several of these bacteria were able to synthesize polyhydroxyalkanoates (PHAs). PHAs are polyesters stored byCorrespondence microorganisms under the presence of considerable amounts of a carbon sourceJorge Quillaguama´n, Center of and deficiency of other essential nutrient such as nitrogen or phosphorous.Biotechnology, Faculty of Sciences and Mangrove forests in Northern Vietnam are saline coastal habitats that have notTechnology, Universidad Mayor de SanSimo´n, Cochabamba, Bolivia. been microbiologically studied. Mangrove ecosystems are, in general, rich inTel/Fax: +591-4-4542895; organic matter, but deficient in nutrients such as nitrogen and phosphorus. WeE-mail: jorgeqs@supernet.com.bo have found about 100 microorganisms that have adapted to mangrove forests by accumulating PHAs. The production of polyesters might therefore be anFunding Information integral part of the carbon cycle in mangrove forests. Three of the strainsThe authors are grateful to the National (ND153, ND97, and QN194) isolated from the Vietnamese forests were identi-Foundation for Science and Technology fied as Bacillus species, while other five strains (QN187, ND199, ND218,Development (NAFOSTED: code 106.03-2010.64) and International Foundation for ND240, and QN271) were phylogenetically close related to the a-proteobacteri-Science (IFS: code F/5021-1) for supporting um Yangia pacifica. These strains were found to accumulate PHAs in noticeablethis work. amounts. Polymer inclusions and chemical structure were studied by transmis- sion electron microscopy and proton nuclear magnetic resonance (NMR) spec-Received: 12 June 2012; Revised: 14 troscopy analyses, respectively. Strains ND153, ND97, QN194, QN187, ND240,September 2012; Accepted: 17 September and QN271 synthesized poly(3-hydroxybutyrate) (PHB) from glucose, whereas2012 strains ND199 and ND218 synthesized poly(3-hydroxybutyrate-co-3-hydroxy-MicrobiologyOpen 2012; 1(4): 395–406 valerate) (PHBV) from this carbohydrate. With the exception of strain QN194, the strains accumulated PHBV when a combination of glucose and propionatedoi: 10.1002/mbo3.44 was included in the culture medium. The polymer yields and cell growth reached by one Bacillus isolate, strain ND153, and one Gram-negative bacterium, strain QN271, were high and worth to be researched further. For experiments performed in shake flasks, strain ND153 reached a maximum PHBV yield of 71 wt% and a cell dry weight (CDW) of 3.6 g/L while strain QN271 attained a maximum PHB yield of 48 wt% and a CDW of 5.1 g/L. Both strain ND153 and strain QN271 may only represent a case in point that exemplifies of the potential that mangrove forests possess for the discovery of novel halophilic and halotoler- ant microorganisms able to synthesize different types of biopolyesters. tional resources in an ecosystem. When a carbon source isIntroduction in excess in the ecosystem, while other essential nutrientMicrobial polyesters, also known as polyhydroxyalkanoates (e.g., nitrogen, phosphorous, or oxygen) is insufficient to(PHAs), are synthesized by various microorganisms as a promote cell growth, the carbon source may be trans-physiological strategy related to the utilization of nutri- formed to polyesters as intracellular carbon and energyª 2012 The Authors. Published by Blackwell Publishing Ltd. This is an open access article under the terms of the Creative 395Commons Attribution License, which permits use ...