Open AccessThe use of an acetoacetyl‐Co A synthase in place of a β‐ketothiolase enhances poly‐3‐hydroxybutyrate production in sugarcane mesophyll cells
Author(s) -
McQualter Richard B.,
Petrasovits Lars A.,
Gebbie Leigh K.,
Schweitzer Dirk,
Blackman Deborah M.,
Chrysanthopoulos Panagiotis,
Hodson Mark P.,
Plan Manuel R.,
Riches James D.,
Snell Kristi D.,
Brumbley Stevens M.,
Nielsen Lars K.
Publication year - 2015
Publication title -
plant biotechnology journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.525
H-Index - 115
eISSN - 1467-7652
pISSN - 1467-7644
DOI - 10.1111/pbi.12298
Subject(s) - polyhydroxyalkanoates , bioplastic , polyhydroxybutyrate , biomass (ecology) , chloroplast , metabolic engineering , yield (engineering) , substrate (aquarium) , atp synthase , raw material , biology , dry weight , photosynthesis , bioenergy , food science , biochemistry , enzyme , botany , biofuel , microbiology and biotechnology , agronomy , materials science , bacteria , gene , ecology , genetics , metallurgy
Summary Engineering the production of polyhydroxyalkanoates ( PHA s) into high biomass bioenergy crops has the potential to provide a sustainable supply of bioplastics and energy from a single plant feedstock. One of the major challenges in engineering C 4 plants for the production of poly[( R )‐3‐hydroxybutyrate] ( PHB ) is the significantly lower level of polymer produced in the chloroplasts of mesophyll (M) cells compared to bundle sheath ( BS ) cells, thereby limiting the full PHB yield‐potential of the plant. In this study, we provide evidence that the access to substrate for PHB synthesis may limit polymer production in M chloroplasts. Production of PHB in M cells of sugarcane is significantly increased by replacing β‐ketothiolase, the first enzyme in the bacterial PHA pathway, with acetoacetyl‐CoA synthase. This novel pathway enabled the production of PHB reaching an average of 6.3% of the dry weight of total leaf biomass, with levels ranging from 3.6 to 11.8% of the dry weight ( DW ) of individual leaves. These yields are more than twice the level reported in PHB ‐producing sugarcane containing the β‐ketothiolase and illustrate the importance of producing polymer in mesophyll plastids to maximize yield. The molecular weight of the polymer produced was greater than 2 × 10 6 Da. These results are a major step forward in engineering a high biomass C 4 grass for the commercial production of PHB .