Enhanced accumulation of important bioproducts in Chlorella vulgaris through AGPase gene silencing coupled with polyethylene glycol treatment

Microalgae with rapid growth rate, ability to be cultivated in non-agricultural land, and producing numerous bioactive compounds have attracted attention for biofuel production and extraction of valuable co-products. This work focuses on the development of an industrially viable Chlorella vulgaris s...

Full description

Saved in:
Bibliographic Details
Published in:Journal of biotechnology Vol. 403; pp. 81 - 92
Main Authors: Saha, Sumedha, Xaxa, Delrin Shaina, Ghosh, Sudip K., Maiti, Mrinal K.
Format: Journal Article
Language:English
Published: Netherlands Elsevier B.V 01.07.2025
Subjects:
acetates
AGPase
biobased products
biorefining
biosynthesis
biotechnology
carbohydrate content
carbon
Carotenoids
Chlorella vulgaris
Chlorella vulgaris - drug effects
Chlorella vulgaris - enzymology
Chlorella vulgaris - genetics
Chlorella vulgaris - growth & development
Chlorella vulgaris - metabolism
coproducts
culture media
exopolysaccharides
fuel production
Gene Silencing
genes
genetically modified organisms
glucose-1-phosphate adenylyltransferase
Glucose-1-Phosphate Adenylyltransferase - genetics
Glucose-1-Phosphate Adenylyltransferase - metabolism
lipid content
liquid state fermentation
metabolites
microalgae
PEG 6000
phosphates
polyethylene glycol
Polyethylene Glycols - chemistry
Polyethylene Glycols - pharmacology
RNA Interference
RNA interference, starch biosynthesis
starch
Starch - biosynthesis
Starch - metabolism
AGPase
PEG 6000
RNA interference, starch biosynthesis
Carotenoids
Chlorella vulgaris
ISSN:0168-1656, 1873-4863, 1873-4863
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Microalgae with rapid growth rate, ability to be cultivated in non-agricultural land, and producing numerous bioactive compounds have attracted attention for biofuel production and extraction of valuable co-products. This work focuses on the development of an industrially viable Chlorella vulgaris strain more suitable for biorefinery by downregulating the ADP-glucose pyrophosphorylase (AGPase) enzyme involved in starch biosynthesis. Transgenic lines of C. vulgaris generated through RNA interference (RNAi) demonstrated diminished starch content with an average of 6.7 % (dry cell weight, DCW) from 10 % (DCW) in the untransformed control, after 5 days of shake flask culture in tris acetate phosphate medium with 16 h:8 h light:dark cycle. Under the same growth condition, the total carbohydrate content decreased by an average of 23.5 %, while the lipid content and carotenoid level improved by an average of 19.3 % and 23 %, respectively, in the RNAi lines compared to the control. RNAi lines showed a higher yield of other important co-products, like protein and exopolysaccharide by an average of 30.6 % and 19.6 %, respectively, compared to the control. Interestingly, when polyethylene glycol (PEG) 6000 (0.5 % w/v) was supplemented in the culture medium of C. vulgaris grown till mid-log phase, RNAi lines along with the untransformed control exhibited enhanced level of valuable metabolites after 7 days of PEG treatment. The average carotenoid content of 25.5 μg/mg was recorded in PEG-treated RNAi lines compared to 15.34 μg/mg in PEG-untreated untransformed control alga. Under the similar growth condition, the average lipid content increased to 22.5 % (DCW) in PEG-treated RNAi lines compared to 16.28 % (DCW) in PEG-untreated untransformed control. Overall, the study encompasses use of genetic engineering tool in combination with the application of biochemical modulator PEG to divert the carbon flux from starch biosynthesis towards improved production of important metabolites in microalga. •AGPase silencing decreased starch content with improved lipid and carotenoid levels.•AGPase downregulation enhanced protein and exopolysaccharide contents.•PEG treatment on RNAi lines positively impacted carotenoid and lipid contents.
Bibliography:ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 23
ISSN:0168-1656
1873-4863
1873-4863
DOI:10.1016/j.jbiotec.2025.04.007