Jatropha Oil as a Potential Carbon Source for PHA Production

Bioplastic Polyhidroxyalknoate (PHA) is a polyester type bioplastic with physicochemical properties resemble to those of polypropilen from petroleum. PHA production was investigated to determine the effect of carbon source on the fermentation process by Ralstonia eutropha. Specifically, Ralstonia eutropha was cultivated in a batch bioreactor to show the dynamics of P(3HB-co-3HV) copolymer production from glucose or fructose as C source. In adition, the effect of volatile fatty acids addition, as stimulator to the copolymer production, was also studied. The operating conditions in a 7 L bioreactor were at temperature 30 oC and pH 7.0. The concentration of carbon source glucose or fructose was 40 g/L, and after 20 hour fermentation, volatile fatty acids were added. With volatile fatty acids addition, the resulting fructose fermentation had PHA content of 32.78%, in which the HV percentage was 11.78%. Meanwhile, the fermentation of glucose, stimulated by volatile fatty acids, gave PHA as much as 20.19% with HV percentage of 8.71%. Therefore,, the Ralstonia eutropha fermentation of fructose as the carbon source gave a higher yield than glucose. Keywords: Volatil Fatty Acid, Fructose, Glucose, PHA, P(3HB-co-3HV), Ralstonia eutropha AbstrakBioplastik polihidroksialkanoat (PHA) adalah bioplastik dari kelompok poliester dengan sifat fisikokimia mirip dengan plastik polipropilen dari minyak bumi. Penelitian ini bertujuan untuk mempelajari pengaruh sumber karbon terhadap poduksi PHA yang dilakukan dengan proses fermentasi menggunakan Ralstonia eutropha. Ralstonia eutropha dikultivasi dalam bioreaktor batch untuk mempelajari dinamika produksi kopolimer P(3HB-co-3HV) dari sumber karbon glukosa atau fruktosa, serta mempelajari pengaruh sumber stimulator asam lemak volatil. Kondisi operasional fermentasi menggunakan bioreaktor 7 L adalah pada temperatur 30 oC dan pH 7. Konsentrasi sumber karbon glukosa atau fruktosa yang digunakan adalah 40 gr/L, dan setelah 20 jam fermentasi ditambahkan asam lemak volatil yang berfungsi sebagai stimulator dalam produksi P(3HB-co-3HV). Panen sel Ralstonia eutropha dilakukan setelah 60 jam. Hasil penelitian menunjukkan fermentasi Ralstonia eutropha dengan substrat fruktosa dan asam lemak volatil sebagai stimulator mempunyai kandungan PHA sebesar 32,78%, dengan kadar HV 11,78%. Pada pemberian substrat glukosa dan asam lemak volatil menunjukkan kandungan PHA sebesar 20,19%, dengan kadar HV 8.71%. Jadi fermentasi Ralstonia eutropha dengan menggunakan substrat fruktosa memberikan yield yang lebih tinggi dibandingkan menggunakan substrat glukosa.Kata Kunci: Asam lemak volatil, fruktosa, glukosa, PHA, P(3HB-co-3HV), Ralstonia eutropha

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Global transcriptional response of Methylorubrum extorquens to formaldehyde stress expands the role of EfgA and is distinct from antibiotic translational inhibition

10.1101/2021.01.07.425672 ◽

2021 ◽

Author(s):

Jannell Bazurto ◽

Siavash Riazi ◽

Simon D'Alton ◽

Daniel E. Deatherage ◽

Eric L. Bruger ◽

...

Keyword(s):

Gene Expression ◽

Carbon Source ◽

Transcriptional Response ◽

Genotoxic Stress ◽

Biological Molecules ◽

Regulatory Control ◽

Translation Inhibition ◽

Translational Inhibition ◽

Potential Carbon

The potency and indiscriminate nature of formaldehyde reactivity upon biological molecules make it a universal stressor. However, some organisms such as Methylorubrum extorquens possess means to rapidly and effectively mitigate formaldehyde-induced damage. EfgA is a recently identified formaldehyde sensor predicted to halt translation in response to elevated formaldehyde as a means to protect cells. Herein, we investigate growth and changes in gene expression to understand how M. extorquens responds to formaldehyde with and without the EfgA-formaldehyde-mediated translational response, and how this mechanism compares to antibiotic-mediated translation inhibition. These distinct mechanisms of translation inhibition have notable differences: they each involve different specific players and in addition, formaldehyde also acts as a general, multi-target stressor and a potential carbon source. We present findings demonstrating that in addition to its characterized impact on translation, functional EfgA allows for a rapid and robust transcriptional response to formaldehyde and that removal of EfgA leads to heightened proteotoxic and genotoxic stress in the presence of increased formaldehyde levels. We also found that many downstream consequences of translation inhibition were shared by EfgA-formaldehyde- and kanamycin-mediated translation inhibition. Our work uncovered additional layers of regulatory control enacted by functional EfgA upon experiencing formaldehyde stress, and further demonstrated the importance this protein plays at both transcriptional and translational levels in this model methylotroph.

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Engineering of Bacillus megaterium for improving PHA production from glycerol

Asia Pacific Journal of Molecular Biology and Biotechnology ◽

10.35118/apjmbb.2019.027.3.07 ◽

2019 ◽

pp. 64-72

Author(s):

Javier Ricardo Gómez Cardozo ◽

Rodrigo Velasco Buscheli ◽

Carlos del Cerro Sánchez ◽

Isabel de la Mata Riesco ◽

Amanda Lucía Mora Martínez

Keyword(s):

Carbon Source ◽

Bacillus Megaterium ◽

Recombinant Strain ◽

Glycerol Dehydrogenase ◽

Wild Type ◽

Pha Production ◽

Glycerol Uptake

There are a few PHA-producer bacteria that can uptake glycerol to produce this biopolymer. Among them, Bacillus megaterium LVN01 has demonstrated to be able to grow up using glycerol as a carbon source. Glycerol dehydrogenase (GD) plays a key role in the synthesis of PHA from glycerol. In this study, the improvement of glycerol uptake by a recombinant strain of B. megaterium carrying pHT01-bmgd was evaluated in order to enhance PHA production. The biomass and PHA production were evaluated and compared to wild-type. It was determined that the PHA produced by both strains was PHB and the highest improvement in PHB yield was 226% at 30 h.

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Screening of bacteria for PHA production using waste glycerol as carbon source and the ability of new strain to produce P(3HB-co-3HV) copolymer

Malaysian Journal of Microbiology ◽

10.21161/mjm.82016 ◽

2016 ◽

Cited By ~ 2

Author(s):

Al-Kaddo, K. B. ◽

Sudesh, K. ◽

Samian, M. R.

Keyword(s):

Carbon Source ◽

Waste Glycerol ◽

Pha Production

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Production of Polyhydroxyalkanoates (PHAs) by Vibrio alginolyticus Strains Isolated from Salt Fields

Molecules ◽

10.3390/molecules26206283 ◽

2021 ◽

Vol 26 (20) ◽

pp. 6283

Author(s):

Hong-Fei Li ◽

Meng-Ru Wang ◽

Lin-Yue Tian ◽

Zheng-Jun Li

Keyword(s):

Carbon Source ◽

Organic Acids ◽

Water Samples ◽

Opportunistic Pathogen ◽

Vibrio Alginolyticus ◽

Culture Temperature ◽

Waste Glycerol ◽

Nacl Concentration ◽

Pha Production ◽

Secondary Carbon

Vibrio alginolyticus is a halophilic organism usually found in marine environments. It has attracted attention as an opportunistic pathogen of aquatic animals and humans, but there are very few reports on polyhydroxyalkanoate (PHA) production using V. alginolyticus as the host. In this study, two V. alginolyticus strains, LHF01 and LHF02, isolated from water samples collected from salt fields were found to produce poly(3-hydroxybutyrate) (PHB) from a variety of sugars and organic acids. Glycerol was the best carbon source and yielded the highest PHB titer in both strains. Further optimization of the NaCl concentration and culture temperature improved the PHB titer from 1.87 to 5.08 g/L in V. alginolyticus LHF01. In addition, the use of propionate as a secondary carbon source resulted in the production of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV). V. alginolyticus LHF01 may be a promising host for PHA production using cheap waste glycerol from biodiesel refining.

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