Table 1 Transcriptomic studies conducted in Chlorella sp.

Chlorella pyrenoidosa FACHB-9

Freshwater

Redirection of central metabolism when CO₂ is deprived

Growth after CO₂ stress

n.a

5% CO₂ → AA

0 h, 1 h, 4 h, 24 h

[21]

Chlorella pyrenoidosa 820

Marine

Transcriptomic changes on different CO₂ conditions

CO₂

n.a

0.16% CO₂

0.04% CO₂

Day 2 0.16% CO₂

Day 2 0.04% CO₂

[20]

Chlorella PY-ZU1

Freshwater

Carbon fixation mechanism of high CO₂-tolerant Chlorella

Growth phase

CO₂

n.a

15% CO₂

Ambient air

12 h, 24 h, 48 h, 72 h 15% CO₂

12 h, 24 h, 48 h, 72 h Ambient air

[13]

Chlorella sp. ABC-001

Marine

Growh specific changes in carbon fixation and lipid accumulation at high CO₂ condition

Growth phase

CO₂

Total fatty acids by GC

10% CO₂

Ambient air

Day 1, 3, 7, 10% CO₂

Day 1, 3, 7, Ambient air

[This study]

Chlorella zofingiensis ATCC 30412

Freshwater

To identify genes and their expression level involved in astaxanthin and TAG biosynthesis

Carbon source

Total fatty acids by GC

Ambient air

Glucose (glc)

6 h

[19]

Chlorella vulgaris UPSI-JRM01

Freshwater

Carbon partitioning toward starch and TAGs under nitrogen stress

Growth after nitrogen stress

Total fatty acids by GC

5% CO₂

Day 1, 4, 8

[18]

Chlorella pyrenoidosa FACHB-10

Freshwater

To affirm the role of lipid turnover and identify differentially expressed transcription factors under nitrogen deprivation

Nitrogen

Fatty acids by GC–MS

Lipid analysis by HPLC–MS

Ambient air

Day 2, 1.5 g/L nitrate

Day 2, 0 g/L nitrate

[23]

Chlorella sp. C596

Marine

Transcriptomic changes before and after nutrient (nitrogen) deprivation

Nitrogen

TAGs by HPLC

15% CO₂ for pH control

109 h, 192 h

[22]

Chlorella sorokiniana G32

Freshwater

To explain high starch accumulation and growth rate under mixotrophic condition

Glucose

Total lipid by gravimetric method

1.25 g/L glc

5 g/L glc

Before & After 1.25 g/L → 5 g/L glc

Before & After 5 g/L → 1.25 g/L glc

[24]

Chlorella sp. TLD6B

Freshwater

To clarify the relationship between salt tolerance and lipid accumulation

Salt stress

Sulfo-phospho-vanillin fluorescence

Ambient air

18 h, 0 M NaCl

18 h, 0.1 M NaCl

18 h, 0.8 M NaCl

[25]

Chlorella sorokiniana UTEX 1602

Freshwater

DEGs in photosynthetic carbon fixation and lipid production under different nitrogen conditions and carbon source

Nitrogen

Carbon source

Nile-red fluorescence

4% glc

4% CO₂

48 h, 0.2% nitrate

48 h,0.8% nitrate

84 h, 0.2% nitrate, heterotrophic

Day 8 0.033% nitrate, 4% CO₂

[17]

Chlorella sp. BLD

Freshwater

Mechanisms of alkali resistance and lipid accumulation in the alkaliphilic microalgae Chlorella sp. BLD

pH

Total lipid by gravimetric method

Ambient air

Day 2 pH 10

Day 2 pH7.5

[36]

Chlorella sp. UMACC 237

Freshwater

Compare transcriptome profile of at ambient (4 °C) versus stress-inducing high (33 °C) temperatures

Temperature

n.a

Ambient air

120 h 4℃

120 h 33℃

[26]

Chlorella sorokiniana NIES-2168

Freshwater

To elucidate the effects glucose assimilation and light intensity

Carbon source

n.a

Ambient air

2% glucose

Day 7 Autotrophic

Day 7 Mixotrophic

[35]

Chlorella vulgaris PKVL 7422

Freshwater

To elucidate the effect of salt stress on metabolism and possible mechanisms of survival

Salt stress

n.a

Ambient air

Control wihout salt stress

2 h, 4 h NaCl 1%

2 h, 4 h NaCl 3%

[37]

Chlorella sp. L5

Freshwater

Revealing the phenol tolerance mechanism

Evolved strain for phenol

n.a

TAP

Day 4, L5 strain

Day 4, L3 strain

[49]

Chlorella pyrenoidosa FACHB-5

Freshwater

Transcriptomic and Physiological Responses during Exposure to 17α-Ethinylestradiol

17α-Ethinylestradiol

(17α EE₂)

n.a

Ambient air

96 h 0 mg/L 17α EE₂

96,h 2 mg/L 17α EE₂

96 h 4 mg/L 17α EE₂

96 h 8 mg/L 17α EE₂

[27]

Chlorella sp. Cv

Freshwater

To understand global response and possible tolerance mechanism against flue gas in an evolved strain

Flue gas

n.a

10% CO₂

Day 1 flue gas

Day 1 10% CO2

[28]