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Production of polyhydroxybutyrate ( PHB ) of high and ultra‐high molecular weight by Azotobacter vinelandii in batch and fed‐batch cultures
Author(s) -
Castillo Tania,
Flores Celia,
Segura Daniel,
Espín Guadalupe,
Sanguino Jonathan,
Cabrera Eliseo,
Barreto Jasmín,
DíazBarrera Alvaro,
Peña Carlos
Publication year - 2017
Publication title -
journal of chemical technology and biotechnology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.64
H-Index - 117
eISSN - 1097-4660
pISSN - 0268-2575
DOI - 10.1002/jctb.5182
Subject(s) - polyhydroxybutyrate , azotobacter vinelandii , nitrogen , chemistry , biopolymer , carbon to nitrogen ratio , carbon fibers , food science , bioplastic , strain (injury) , polyhydroxyalkanoates , nuclear chemistry , materials science , chemical engineering , organic chemistry , polymer , bacteria , waste management , nitrogen fixation , composite material , biology , nitrogenase , genetics , anatomy , composite number , engineering
BACKGROUND Polyhydroxybutyrate ( PHB ) is a biopolymer with thermo‐mechanical properties like those of plastics produced by the petrochemical industry. These properties are improved in PHBs of high or ultra‐high weight average molecular weight. Azotobacter vinelandii OPNA is a potential producer of large quantities of PHB , having ultra‐high molecular weight by fed‐batch production strategies. RESULTS In batch and fed‐batch cultures at different carbon–nitrogen molar ratios (10, 14 and 18), the OPNA strain produced PHB of high and ultra‐high weight average molecular weight, with values between 2.3 and 6.6 MDa . In this strain, the weight average molecular weight was highly dependent on the initial carbon–nitrogen ratio, reaching the highest value (6.6 MDa ) in batch cultures conducted with a carbon–nitrogen ratio of 18 and the lowest (2.3) with a carbon–nitrogen ratio of 10. On the other hand, using a two feeding‐pulses fed‐batch strategy, the highest global PHB volumetric productivity (0.56 g L −1 h −1 ) and polymer concentration (27.6 g L −1 ) were obtained. CONCLUSION The OPNA strain accumulated up to 80% of PHB of ultra‐high molecular weight as a function of the initial carbon–nitrogen molar ratio. Using a simple fed‐batch strategy of two feeding‐pulses was possible to produce up to 27 g L −1 of PHB . © 2016 Society of Chemical Industry