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Rodge SP, Shende KS, Patil NP. Polyhydroxyalkanoate biosynthesis and optimisation of thermophilic Geobacillus stearothermophilus strain K4E3_SPR_NPP. Extremophiles 2023; 27:13. [PMID: 37349574 DOI: 10.1007/s00792-023-01300-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 06/04/2023] [Indexed: 06/24/2023]
Abstract
Polyhydroxyalkanoates (PHA) can be used to combat the challenges associated with plastic because it is biodegradable and can be produced from renewable resources. Extremophiles are considered to be potential PHA producers. An initial screening for the PHA synthesizing ability of a thermophilic bacteria Geobacillus stearothermophilus strain K4E3_SPR_NPP was carried out using Sudan black B staining. Nile red viable colony staining was used to further verify that the isolates produced PHA. Crotonic acid assays were used to determine the concentrations of PHA. The bacteria showed 31% PHA accumulation per dry cell weight (PHA/DCW) when glucose was used as a carbon source for growth. The molecule was identified to be medium chain length PHA, A copolymer of PHA containing poly(3-hydroxybutyrate)-poly(3-hydroxyvalerate)-poly(3-hydroxyhexanoate) (PHB-PHV-PHHX) using 1H-NMR. Six carbon sources and four nitrogen sources were screened for the synthesis of maximum PHA content, of which lactose and ammonium nitrate showed 45% and 53% PHA/DCW respectively. The important factors in the experiment are identified using the Plackett-Burman design, and optimization is performed using the response surface method. Response surface methodology was used to optimize the three important factors, and the maximum biomass and PHA productions were discovered. Optimal concentrations yielded a maximum of 0.48 g/l biomass and 0.32 g/l PHA, measuring 66.66% PHA accumulation. Dairy industry effluent was employed for the synthesis of PHA, yielding 0.73 g/l biomass and 0.33 g/l PHA, measuring 45% PHA accumulation. These findings add credibility to the possibility of adopting thermophilic isolates for PHA production using low-cost substrates.
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Yootoum A, Jantanasakulwong K, Rachtanapun P, Moukamnerd C, Chaiyaso T, Pumas C, Tanadchangsaeng N, Watanabe M, Fukui T, Insomphun C. Characterization of newly isolated thermotolerant bacterium Cupriavidus sp. CB15 from composting and its ability to produce polyhydroxyalkanoate from glycerol. Microb Cell Fact 2023; 22:68. [PMID: 37046250 PMCID: PMC10091600 DOI: 10.1186/s12934-023-02059-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 03/09/2023] [Indexed: 04/14/2023] Open
Abstract
BACKGROUND This study aimed to isolate a novel thermotolerant bacterium that is capable of synthesizing polyhydroxyalkanoate from glycerol under high temperature conditions. RESULTS A newly thermotolerant polyhydroxyalkanoate (PHA) producing bacterium, Cupriavidus sp. strain CB15, was isolated from corncob compost. The potential ability to synthesize PHA was confirmed by detection of PHA synthase (phaC) gene in the genome. This strain could produce poly(3-hydroxybutyrate) [P(3HB)] with 0.95 g/L (PHA content 75.3 wt% of dry cell weight 1.24 g/L) using glycerol as a carbon source. The concentration of PHA was enhanced and optimized based on one-factor-at-a-time (OFAT) experiments and response surface methodology (RSM). The optimum conditions for growth and PHA biosynthesis were 10 g/L glycerol, 0.78 g/L NH4Cl, shaking speed at 175 rpm, temperature at 45 °C, and cultivation time at 72 h. Under the optimized conditions, PHA production was enhanced to 2.09 g/L (PHA content of 74.4 wt% and dry cell weight of 2.81 g/L), which is 2.12-fold compared with non-optimized conditions. Nuclear magnetic resonance (NMR) analysis confirmed that the extracted PHA was a homopolyester of 3-hydyoxybutyrate. CONCLUSION Cupriavidus sp. strain CB15 exhibited potential for cost-effective production of PHA from glycerol.
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Affiliation(s)
- Anuyut Yootoum
- Interdisciplinary Program in Biotechnology, Graduate School, Chiang Mai University, Chiang Mai, 50200, Thailand
| | - Kittisak Jantanasakulwong
- School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, 155 Mae Hia, Mueang, Chiang Mai, 50100, Thailand
- Cluster of Agro Bio-Circular-Green Industry (Agro BCG), Chiang Mai University, Chiang Mai, 50100, Thailand
| | - Pornchai Rachtanapun
- School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, 155 Mae Hia, Mueang, Chiang Mai, 50100, Thailand
- Cluster of Agro Bio-Circular-Green Industry (Agro BCG), Chiang Mai University, Chiang Mai, 50100, Thailand
| | - Churairat Moukamnerd
- School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, 155 Mae Hia, Mueang, Chiang Mai, 50100, Thailand
| | - Thanongsak Chaiyaso
- School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, 155 Mae Hia, Mueang, Chiang Mai, 50100, Thailand
- Cluster of Agro Bio-Circular-Green Industry (Agro BCG), Chiang Mai University, Chiang Mai, 50100, Thailand
| | - Chayakorn Pumas
- Department of Biology, Faculty of Science, Chiang Mai University, 239 Huaykaew Road, Suthep, Mueang, Chiang Mai, 50200, Thailand
| | - Nuttapol Tanadchangsaeng
- College of Biomedical Engineering, Rangsit University, 52/347 Lak-Hok, Pathumthani, 12000, Thailand
| | - Masanori Watanabe
- Graduate School of Agriculture, Yamagata University, 1-23 Wakaba-Machi, Tsuruoka, Yamagata, 997-8555, Japan
| | - Toshiaki Fukui
- School of Life Science and Technology, Tokyo Institute of Technology, 4259 Nagatsuta-Cho, Midori-Ku, Yokohama, Kanagawa, 226-8503, Japan
| | - Chayatip Insomphun
- School of Agro-Industry, Faculty of Agro-Industry, Chiang Mai University, 155 Mae Hia, Mueang, Chiang Mai, 50100, Thailand.
- Cluster of Agro Bio-Circular-Green Industry (Agro BCG), Chiang Mai University, Chiang Mai, 50100, Thailand.
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Alsafadi D, AljaririAlhesan JS, Mansoura A, Oqdeha S. Production of polyhydroxyalkanoate from sesame seed wastewater by sequencing batch reactor cultivation process of Haloferax Mediterranei. ARAB J CHEM 2023. [DOI: 10.1016/j.arabjc.2023.104584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
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4
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Argiz L, Val Del Río Á, Correa-Galeote D, Rodelas B, Mosquera-Corral A. Simplified engineering design towards a competitive lipid-rich effluents valorization. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 317:115433. [PMID: 35751251 DOI: 10.1016/j.jenvman.2022.115433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2022] [Revised: 05/14/2022] [Accepted: 05/26/2022] [Indexed: 06/15/2023]
Abstract
Medium- and long-chain fatty acids and glycerol contained in the oily fraction of many food-industry effluents are excellent candidates to produce biobased high-value triacylglycerides (TAGs) and polyhydroxyalkanoates (PHAs). The typical process configuration for TAGs recovery from lipid-rich streams always includes two steps (culture enrichment plus storage compounds accumulation) whereas, for PHAs production, an additional pretreatment of the substrate for the obtainment of soluble volatile fatty acids (VFAs) is required. To simplify the process, substrate hydrolysis, culture enrichment, and accumulation (TAG and PHA storage) were coupled here in a single sequencing batch reactor (SBR) operated under the double growth limitation strategy (DGL) and fed in pulses with industrial waste fish oil during the whole feast phase. When the SBR was operated in 12 h cycles, it was reached up to 51 wt % biopolymers after only 6 h of feast (TAG:PHA ratio of 50:51; 0.423 CmmolBIOP/CmmolS). Daily storage compound production was observed to be over 25% higher than the reached when enrichment and accumulation stages were carried in separate operational units. Increasing the feast phase length from 6 to 12 h (18 h cycle) negatively affected the DGL strategy performance and hence system storage capacity, which was recovered after also extending the famine phase in the same proportion (24 h cycle). Besides, the carbon influx during the feast phase was identified as a key operational parameter controlling storage compounds production and, together with the C/N ratio, culture selection. The different cycle configurations tested clearly modulated the total fungal abundances without no significant differences in the size of the bacterial populations. Several PHA and TAG producers were found in the mixed culture although the PHA and TAG productions were poorly associated with the increased relative abundances (RAs) of specific operational taxonomic units (OTUs).
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Affiliation(s)
- Lucía Argiz
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain.
| | - Ángeles Val Del Río
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain
| | - David Correa-Galeote
- Department of Microbiology, Faculty of Pharmacy, University of Granada, 18001, Granada, Andalucía, Spain; Microbiology and Environmental Technology Section, Department of Microbiology, Faculty of Pharmacy, University of Granada, 18001, Granada, Andalucía, Spain
| | - Belén Rodelas
- Department of Microbiology, Faculty of Pharmacy, University of Granada, 18001, Granada, Andalucía, Spain; Microbiology and Environmental Technology Section, Department of Microbiology, Faculty of Pharmacy, University of Granada, 18001, Granada, Andalucía, Spain
| | - Anuska Mosquera-Corral
- CRETUS Institute, Department of Chemical Engineering, Universidade de Santiago de Compostela, 15782, Santiago de Compostela, Galicia, Spain
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5
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Miao C, Meng D, Liu Y, Wang F, Chen L, Huang Z, Fan X, Gu P, Li Q. Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) in metabolically recombinant Escherichia coli. Int J Biol Macromol 2021; 193:956-964. [PMID: 34751142 DOI: 10.1016/j.ijbiomac.2021.10.183] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/08/2021] [Accepted: 10/23/2021] [Indexed: 11/25/2022]
Abstract
In this study, a phaCR gene encoding PHA synthase was identified in Rhodoligotrophos defluvii which was adjacent to β-ketothiolase encoded by phaAR gene and acetoacetyl-CoA reductase encoded by phaBR gene. Amino acid comparison of PhaCR showed the highest homology of 65.98% with PhaC of R. appendicifer, while its homology with typical class I PHA synthase in Cupriavidus necator was only 42.54%. PHA synthesis genes were then transformed into E. coli harboring phaCABR and phaCRABC which were cultured with 15 g/L glucose respectively, and 20.46 wt% and 16.95 wt% of CDW for poly(3-hydroxybutyrate) (PHB) were accumulated respectively. To further explore the effect of substrate specificity for PHA production, the ptsG gene was then deleted and 15 g/L glucose and 1.5 g/L propionate were co-employed as carbon sources, which enabled the synthesis of poly(3HB-co-3HV) copolymer. As a result, poly(3HB-co-3HV) was accumulated up to 24.74 wt% of CDW, and the highest content of 3-hydroxyvalerate (3HV) was 10.86 mol%. The Td5 was 260 °C, which implied that it possessed good thermal stability, and the Mw of GPC in recombinant strains were between 22 and 26 × 104 g/mol, and the highest PDI was 3.771. The structure of poly (3HB-co-3HV) copolymer was determined through 1H NMR analysis.
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Affiliation(s)
- Changfeng Miao
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Dong Meng
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Yuling Liu
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Fang Wang
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Lu Chen
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Zhaosong Huang
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Xiangyu Fan
- School of Biological Science and Technology, University of Jinan, Jinan, China
| | - Pengfei Gu
- School of Biological Science and Technology, University of Jinan, Jinan, China.
| | - Qiang Li
- School of Biological Science and Technology, University of Jinan, Jinan, China.
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6
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Romero Soto L, Thabet H, Maghembe R, Gameiro D, Van-Thuoc D, Dishisha T, Hatti-Kaul R. Metabolic potential of the moderate halophile Yangia sp. ND199 for co-production of polyhydroxyalkanoates and exopolysaccharides. Microbiologyopen 2021; 10:e1160. [PMID: 33650793 PMCID: PMC7892980 DOI: 10.1002/mbo3.1160] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/20/2020] [Accepted: 12/22/2020] [Indexed: 12/02/2022] Open
Abstract
Yangia sp. ND199 is a moderately halophilic bacterium isolated from mangrove samples in Northern Vietnam, which was earlier reported to grow on several sugars and glycerol to accumulate poly(hydroxyalkanoates) (PHA). In this study, the potential of the bacterium for co‐production of exopolysaccharides (EPS) and PHA was investigated. Genome sequence analysis of the closely related Yangia sp. CCB‐M3 isolated from mangroves in Malaysia revealed genes encoding enzymes participating in different EPS biosynthetic pathways. The effects of various cultivation parameters on the production of EPS and PHA were studied. The highest level of EPS (288 mg/L) was achieved using sucrose and yeast extract with 5% NaCl and 120 mM phosphate salts but with modest PHA accumulation (32% of cell dry weight, 1.3 g/L). Growth on fructose yielded the highest PHA concentration (85% of CDW, 3.3 g/L) at 90 mM phosphate and higher molecular weight EPS at 251 mg/L yield at 120 mM phosphate concentration. Analysis of EPS showed a predominance of glucose, followed by fructose and galactose, and minor amounts of acidic sugars.
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Affiliation(s)
- Luis Romero Soto
- Division of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, Lund, Sweden.,Instituto de Investigación y Desarrollo de Procesos Químicos, Universidad Mayor de San Andrés, La Paz, Bolivia
| | - Habib Thabet
- Division of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, Lund, Sweden.,Food Science and Technology Department, Ibb University, Ibb, Yemen
| | - Reuben Maghembe
- Division of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, Lund, Sweden.,Department of Molecular Biology and Biotechnology, College of Natural and Applied Sciences, University of Dar es Salaam, Dar es Salaam, Tanzania
| | - Denise Gameiro
- Division of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, Lund, Sweden
| | - Doan Van-Thuoc
- Department of Biotechnology and Microbiology, Faculty of Biology, Hanoi National University of Education, Hanoi, Vietnam
| | - Tarek Dishisha
- Department of Pharmaceutical Microbiology and Immunology, Faculty of Pharmacy, Beni-Suef University, Beni-Suef, Egypt
| | - Rajni Hatti-Kaul
- Division of Biotechnology, Center for Chemistry and Chemical Engineering, Lund University, Lund, Sweden
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7
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Sato S, Ino K, Ushimaru K, Wada K, Saika A, Fukuoka T, Ohshiman K, Morita T. Evaluating haloarchaeal culture media for ultrahigh-molecular-weight polyhydroxyalkanoate biosynthesis by Haloferax mediterranei. Appl Microbiol Biotechnol 2021; 105:6679-6689. [PMID: 34459953 DOI: 10.1007/s00253-021-11508-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2021] [Revised: 08/03/2021] [Accepted: 08/06/2021] [Indexed: 10/20/2022]
Abstract
A series of culture media for haloarchaea were evaluated to optimize the production of ultrahigh-molecular-weight (UHMW) poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) by Haloferax mediterranei. Cells of H. mediterranei grew (> 1 g/L of dry cell weight) and accumulated PHBV upon flask cultivation in 10 medium types with neutral pH and NaCl concentration > 100 g/L. Molecular weight and compositional analysis revealed that the number-average molecular weight (Mn) of PHBV produced with six selected types of media ranged from 0.8 to 3.5 × 106 g/mol and the 3-hydroxyvalerate (3HV) composition ranged from 8 to 36 mol%. Cultivation in two NBRC media, 1214 and 1380, resulted in the production of PHBV with an Mn of more than 3.0 × 106 g/mol and a weight-average molecular weight of more than 5.0 × 106 g/mol, indicating the production of UHMW-PHBV. These culture media contained small amount of complex nutrients like yeast extract and casamino acids, suggesting that H. mediterranei likely produced UHMW-PHBV on poor nutrient condition. Haloferax mediterranei grown in NBRC medium 1380 produced PHBV with the highest 3HV composition. A solvent-cast film of UHMW-PHBV with 26.4 mol% 3HV produced from 1-L flask cultivation with NBRC medium 1380 was found to be flexible and semi-transparent. Thermal analysis of the UHMW-PHBV cast film revealed melting and glass-transition temperatures of 90.5 °C and - 2.7 °C, respectively. KEY POINTS: • Haloarchaeal culture media were evaluated to produce UHMW-PHBV by H. mediterranei. • UHMW-PHBV with varied molecular weight was produced dependent on culture media. • Semi-transparent film could be made from UHMW-PHBV with 26.4 mol% 3HV.
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Affiliation(s)
- Shun Sato
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan.
| | - Kotaro Ino
- Sumitomo Forestry Co., LTD., 3-2 Midorigahara, Tsukuba, Ibaraki, 300-2646, Japan
| | - Kazunori Ushimaru
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
| | - Keisuke Wada
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
| | - Azusa Saika
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
| | - Tokuma Fukuoka
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
| | - Koichi Ohshiman
- Sumitomo Forestry Co., LTD., 3-2 Midorigahara, Tsukuba, Ibaraki, 300-2646, Japan
| | - Tomotake Morita
- Research Institute for Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology (AIST), Central 5-2, 1-1-1 Higashi, Tsukuba, Ibaraki, 305-8565, Japan
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8
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Kasirajan L, Maupin-Furlow JA. Halophilic archaea and their potential to generate renewable fuels and chemicals. Biotechnol Bioeng 2020; 118:1066-1090. [PMID: 33241850 DOI: 10.1002/bit.27639] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/27/2020] [Accepted: 11/17/2020] [Indexed: 12/16/2022]
Abstract
Lignocellulosic biofuels and chemicals have great potential to reduce our dependence on fossil fuels and mitigate air pollution by cutting down on greenhouse gas emissions. Chemical, thermal, and enzymatic processes are used to release the sugars from the lignocellulosic biomass for conversion to biofuels. These processes often operate at extreme pH conditions, high salt concentrations, and/or high temperature. These harsh treatments add to the cost of the biofuels, as most known biocatalysts do not operate under these conditions. To increase the economic feasibility of biofuel production, microorganisms that thrive in extreme conditions are considered as ideal resources to generate biofuels and value-added products. Halophilic archaea (haloarchaea) are isolated from hypersaline ecosystems with high salt concentrations approaching saturation (1.5-5 M salt concentration) including environments with extremes in pH and/or temperature. The unique traits of haloarchaea and their enzymes that enable them to sustain catalytic activity in these environments make them attractive resources for use in bioconversion processes that must occur across a wide range of industrial conditions. Biocatalysts (enzymes) derived from haloarchaea occupy a unique niche in organic solvent, salt-based, and detergent industries. This review focuses on the use of haloarchaea and their enzymes to develop and improve biofuel production. The review also highlights how haloarchaea produce value-added products, such as antibiotics, carotenoids, and bioplastic precursors, and can do so using feedstocks considered "too salty" for most microbial processes including wastes from the olive-mill, shell fish, and biodiesel industries.
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Affiliation(s)
- Lakshmi Kasirajan
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA.,Division of Crop Improvement, ICAR Sugarcane Breeding Institute, Coimbatore, India
| | - Julie A Maupin-Furlow
- Department of Microbiology and Cell Science, University of Florida, Gainesville, Florida, USA.,Genetics Institute, University of Florida, Gainesville, Florida, USA
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Alsafadi D, Ibrahim MI, Alamry KA, Hussein MA, Mansour A. Utilizing the crop waste of date palm fruit to biosynthesize polyhydroxyalkanoate bioplastics with favorable properties. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 737:139716. [PMID: 32526568 DOI: 10.1016/j.scitotenv.2020.139716] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Revised: 05/23/2020] [Accepted: 05/24/2020] [Indexed: 05/12/2023]
Abstract
Polyhydroxyalkanoate (PHA), a family of biodegradable and renewable biopolymers that could potentially play a significant role in bioeconomy. In this study we investigated the potential of date waste (DW) biomass as feedstock to produce PHA by the halophilic archaeon Haloferax mediterranei. The concentration of essential trace elements for H. mediterranei cells during growth and PHA biopolymer accumulation was optimized. A maximum cell dry mass of (CDM) (12.8 g L-1) and PHA concentration of (3.20 g L-1) were achieved in DW extract media that was not supplemented with trace elements, indicating that DW is a promising source for trace elements. The cultivation was scaled-up to fed-batch bioreactor fermentations under non-sterile conditions and resulted in CDM and PHA content of 18.0 g L-1 and 25%, respectively. The produced PHA was confirmed to be poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) with high 3-hydroxyvalerate (3 HV) content of 18.0 mol%. This 3 HV molar percent was achieved without the addition of expensive precursors. The PHBV is of high molecular weight (746.0 kDa) and narrow polydispersity (PDI = 1.5), and displayed reduced melting at 148.1 °C. The X-ray diffraction (XRD) analysis showed that the PHBV has amorphous nature which increases the degradation rates and workability of the biopolymer. The isotopic ratio 13C/12C (δ 13C) for PHBV was found to be - 19.1‰, which indicated that H. mediterranei prefers lighter bonds to break and uses the lighter atoms for the biosynthesis of PHBV.
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Affiliation(s)
- Diya Alsafadi
- Biocatalysis and Biosynthesis Research Unit, Foundational Science Research Division, Royal Scientific Society, Amman 11941, Jordan.
| | - Mohammad I Ibrahim
- Department of Chemistry, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Khalid A Alamry
- Department of Chemistry, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Mahmoud A Hussein
- Department of Chemistry, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Aya Mansour
- Biocatalysis and Biosynthesis Research Unit, Foundational Science Research Division, Royal Scientific Society, Amman 11941, Jordan
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Alsafadi D, Al-Mashaqbeh O, Mansour A, Alsaad M. Optimization of nitrogen source supply for enhanced biosynthesis and quality of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) by extremely halophilic archaeon Haloferax mediterranei. Microbiologyopen 2020; 9:e1055. [PMID: 32410392 PMCID: PMC7424248 DOI: 10.1002/mbo3.1055] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2020] [Revised: 04/13/2020] [Accepted: 04/20/2020] [Indexed: 11/06/2022] Open
Abstract
The extreme halophilic archaeon, Haloferax mediterranei can accumulate polyhydroxyalkanoate (PHA) from different renewable resources. To enhance the biosynthesis and quality of PHA, H. mediterranei cultivation media was optimized at different C/N ratios using glucose as the main carbon source. Three sets of media (yeast extract [YE], NH4 Cl and combination of YE and NH4 Cl) were prepared at different nitrogen concentrations to achieve C/N ratios of 9, 20, and 35, respectively. The media containing YE (organic nitrogen source) produced a higher growth rate of H. mediterranei than NH4 Cl (inorganic source) at all tested C/N ratios. The highest PHA accumulation (18.4% PHA/cell dry mass) was achieved in a media that combined YE with NH4 Cl at a C/N ratio of 20. Analysis of the produced polymers revealed the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBHV) with different 3-hydroxyvalerate (3HV) content. The polymers produced from YE and the combined media have greater 3HV content (10 mol%) than those polymers recovered from NH4 Cl (1.5 mol%). Resultingly, PHBHV from YE and the combined media displayed reduced melting points at 144°C. The nitrogen type/concentration was found to also have an impact on the molecular weights and polydispersity indices of the produced biopolymers. Furthermore, the tensile strengths were found to vary with the best tensile strength (14.4 MPa) being recorded for the polymer recovered from YE at C/N = 9. Interestingly, the tensile strength of PHBHV was significantly higher than petroleum-based polyethylene (13.5 MPa), making it a much more suitable bioplastic for industrial application.
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Affiliation(s)
- Diya Alsafadi
- Biosynthesis and Biocatalysis Research Unit, Foundational Science Research Division, Royal Scientific Society, Amman, Jordan
| | | | - Aya Mansour
- Biosynthesis and Biocatalysis Research Unit, Foundational Science Research Division, Royal Scientific Society, Amman, Jordan
| | - Majd Alsaad
- Biosynthesis and Biocatalysis Research Unit, Foundational Science Research Division, Royal Scientific Society, Amman, Jordan
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