Affiliation:
1. State Key Laboratory of Subtropical Silviculture, School of Forestry and Biotechnology, Zhejiang A&F University, Lin’an , Hangzhou, China
Abstract
ABSTRACT
Microalgae are a potential source of biodiesel owing to their simple structure and high biomass and lipid production rates. Here, we demonstrate that fatty acid (FA) contents can be altered in
Chlorella
sp. JB6 in the presence of sodium bicarbonate (NaHCO
3
). We cloned the key genes necessary for FA
de novo
synthesis conserved in JB6, including
biotin carboxyl carrier protein
(
BCCP
),
β-carboxyltransferase
(
β-CT
),
malonyl CoA-ACP malonyl transferase
(
MCMT
),
3-ketoacyl-ACP reductase
(
KAR
),
β-ketoacyl-[acyl carrier protein] synthase I
(
KASI
), and
KASII
, and successfully transferred plasmids carrying these genes into JB6 cells. We found that overexpression of
BCCP
,
MCMT
,
KASI
,
and KASII
inhibited the growth of JB6 cells and decreased their resistance to NaHCO
3
. Notably, ectopic expression of these genes promoted very long-chain saturated FA (>20 C) accumulation. Taken together, we demonstrate that these genes are critical for JB6 growth and resistance to NaHCO
3
and can be used for metabolic engineering.
IMPORTANCE
Fatty acid (FA) contents can be altered in Chlorella JB6 in the presence of sodium bicarbonate (NaHCO
3
). Overexpression of the FA
de novo
synthesis genes inhibited the growth of JB6 cells and decreased their resistance to NaHCO
3
, but these transgenic JB6 strains could grow in a medium containing as high as 300 mM NaHCO
3
. In JB6, ectopic expression of the FA
de novo
synthesis genes increased the synthesis of very long-chain saturated FA (> 20C).
Funder
MOST | National Natural Science Foundation of China
Publisher
American Society for Microbiology
Subject
Infectious Diseases,Cell Biology,Microbiology (medical),Genetics,General Immunology and Microbiology,Ecology,Physiology