Research articles
ScienceAsia 50 (2024):ID 2024024 1-8 |doi:
10.2306/scienceasia1513-1874.2024.024
Enhanced productions of poly-3-hydroxybutyrate and
glycogen in cyanobacterium Synechocystis sp. PCC 6803 by
disrupting related biosynthetic pathways under phosphorus
deprivation
Janine Kaewbai-ngama,b, Tanakarn Monshupaneea,*
ABSTRACT: Under normal growth (NORMAL) condition with adequate supply of phosphorus and nitrogen, the wellstudied cyanobacterium Synechocystis wild type (WT) produced a high biomass level but subtle contents of the two
biopolymers: poly-3-hydroxybutyrate (PHB) and glycogen. In contrast, under nitrogen deprivation, growth of WT was
terminated, while the accumulations of PHB and glycogen were increased. Thus, a strain and a cultivation strategy
that simultaneously allows both biomass production and the increased storages of the two biopolymers are desirable.
Here, under phosphorus deprivation (-P), WT grew and still produced biomass at 850 mg/l (accounting for 62%
of the biomass level obtained under NORMAL cultivation) with slightly increased contents of PHB and glycogen at
0.5% and 5.5% (w/w DW), respectively. Under -P, the ?G mutant with the inactivated glycogen synthesis produced
biomass at 751 mg/l and enhanced PHB accumulation to 4.9% (w/w DW), corresponding to PHB production of
36 mg/l. The ?HP mutant with the inactivation of both PHB and hydrogen-gas syntheses under -P produced biomass at
713 mg/l and increased glycogen storage to 14.6% (w/w DW), corresponding to glycogen production of 118 mg/l. The
significantly reduced levels of both chlorophyll and phycobilisomes (the main photosynthetic protein complex) found
in ?G and ?HP mutants under -P suggested that photosynthetic proteins were degraded into amino acids which might
subsequently be used for PHB and glycogen syntheses. The results indicated that the metabolic engineering combined
with -P cultivation concurrently allowed cell growth and increased the production of two biopolymers in the studied
Synechocystis.
Download PDF
0 Downloads 369 Views
a |
Department of Biochemistry, Faculty of Science, Chulalongkorn University, Bangkok 10330 Thailand |
b |
Program in Biotechnology, Faculty of Science, Chulalongkorn University, Bangkok 10330 Thailand |
* Corresponding author, E-mail: tanakarn.m@chula.ac.th
Received 16 Jun 2023, Accepted 14 Dec 2023
|