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Study of recombinant bacteria and metabolic flux analysis to biosynthesize the biodegradable copolymer poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) [P(3HB-co-3HHx)].

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Author(s):
Thatiane Teixeira Mendonça
Total Authors: 1
Document type: Doctoral Thesis
Press: São Paulo.
Institution: Universidade de São Paulo (USP). Instituto de Ciências Biomédicas (ICB/SDI)
Defense date:
Examining board members:
Luiziana Ferreira da Silva; Welington Luiz de Araujo; Heloiza Ramos Barbosa; Joao Carlos Monteiro de Carvalho; Rosane Aparecida Moniz Piccoli
Advisor: Luiziana Ferreira da Silva; José Gregorio Cabrera Gomez
Abstract

The biodegradable copolymer poly(3-hydroxybutyrate-co-3-hydroxyhexanoate) P(3HB-co-3HHx) is a polyhydroxyalkanoate (PHA) presenting various applications. The bacterium Burkholderia sacchari accumulated P(3HB-co-2mol%3HHx) from glucose and hexanoic acid. In order to obtain P(3HB-co-3HHx) with different 3HHx amounts by B. sacchari, recombinant strains containing phaPCJ operon genes from Aeromonas spp were constructed. Recombinant strains produced P(3HB-co-3HHx) from hexanoic, lauric and linoleic acids, with contents of 3HHx ranging from 1.88 to 18 mol%. Experiments with the recombinant in bioreactor, fed in the accumulation phase by glucose 140 g.l-1and hexanoic acid 0-45 g.l-1, resulted in copolymers with compositions ranging from 0 to 20 mol% of 3HHx. The copolymers produced were extracted and analyzed for physical properties. The metabolic flux analysis indicated that PHA production can be increased by modifying the central metabolism and deleting/ overexpressing genes. (AU)