Microalgae Species Quiz

Questions and Answers

Which microalga has the highest lipid productivity?

Isochrysis sp.

Nannochloropsis sp.

Schizochytrium sp. (correct)

Dunaliella primolecta

Which of the following represents a challenge in microalgae biotechnology?

Operating costs (correct)

Low nutrient requirements

Ability to grow in freshwater

High oil content

Which microalga species is listed with a lipid productivity range of 15-23?

Nannochloris sp.

Dunaliella salina

Tetraselmis suecica (correct)

Prymnesium parvum

What is one reason microalgae are being used for biofuels?

They can grow in aquatic environments. Signup and view all the answers

Which of the following processes is involved in lipid biosynthesis in microalgae?

Packaging of TAGs into lipid droplets Signup and view all the answers

Which microalga has the lowest reported lipid productivity?

Spirulina platensis Signup and view all the answers

What is the first stage of cultivation in the pilot scale production of the selected strains?

Nitrogen replete condition Signup and view all the answers

During which condition does lipid or TAG accumulation occur?

Nitrogen starvation condition Signup and view all the answers

How many strains were able to survive the nitrogen starvation condition?

Four strains Signup and view all the answers

What type of photobioreactor represents the intermediate stage of biofuels production scale-up?

Pilot scale photobioreactors Signup and view all the answers

What media was used for testing the microalgae strains during the experiments?

BG11.NaCl 1% (wt/v) Signup and view all the answers

Which metabolic processes are involved in carbon partitioning in algae?

Lipid, protein, and carbohydrate production Signup and view all the answers

What is the overall aim of the two-stage cultivation strategy?

Maximize biomass and lipid accumulation Signup and view all the answers

What is the role of CO2 in the carbon partitioning of algae?

To provide carbon for biomass synthesis Signup and view all the answers

What characteristic is noted about the twelve surviving species?

They produce lipids efficiently. Signup and view all the answers

At what temperature do the surviving species show high growth rates?

40 ⁰C Signup and view all the answers

Which of the following is an implication of high lipid production in these species?

They may have potential applications in biofuels. Signup and view all the answers

Which statement is true regarding lipid production in the twelve species?

These species show high lipid production at 40 ⁰C. Signup and view all the answers

What can be inferred about the environmental conditions suitable for these surviving species?

They require stable, warm temperatures. Signup and view all the answers

What is the relationship between temperature and growth rate in these species?

Growth rate increases with rising temperatures up to a threshold. Signup and view all the answers

How are these surviving species categorized?

As uni-algal species. Signup and view all the answers

Which benefit do these twelve species most likely provide to their ecosystems?

They assist in carbon dioxide absorption. Signup and view all the answers

What is the average lipid content for microalgal species at day 0?

$2.0 imes 10^{-12}$ g/cell Signup and view all the answers

Which lipid content is recorded at day 7?

$1.5 imes 10^{-12}$ g/cell Signup and view all the answers

How much lipid content is observed at day 17?

$1.0 imes 10^{-12}$ g/cell Signup and view all the answers

Which of the following is not a step in molecular identification of the microalgal species?

Analyze lipid content Signup and view all the answers

What is the purpose of identifying resistant microalgal species?

To increase biofuel production Signup and view all the answers

In which stage is the average lipid content lowest for the given observation periods?

Day 0 Signup and view all the answers

What type of species are the focus of the study?

Microalgal resistant species Signup and view all the answers

What might be inferred about the trend of lipid content over time based on the data?

It stabilizes after day 7. Signup and view all the answers

Which K value is noted multiple times in the data?

K 5 Signup and view all the answers

What is the main focus of biofuel production in relation to the microalgal species studied?

Increasing lipid content for fuel Signup and view all the answers

What is the yield of neutral lipids from 100 g of Desmodesmus intermedius biomass?

14 g Signup and view all the answers

Which measured parameter is NOT listed in the provided content?

pH level Signup and view all the answers

Which strain produced a slightly lower percentage of neutral lipids?

Synechocystis sp.PCC 6803 Signup and view all the answers

What is the light intensity parameter used in the cultivation process?

Not mentioned Signup and view all the answers

How long was the running time for the pilot scale cultivation?

40 days Signup and view all the answers

What method was used to extract neutral lipids?

Hexane extraction Signup and view all the answers

What is the biomass nitrogen content percentage for the microalgae used?

50% Signup and view all the answers

What is the working volume of the bioreactor used in the pilot scale cultivation?

10 Liters Signup and view all the answers

Study Notes

Microalgae Species and Their Characteristics

Various species of microalgae have shown distinct growth rates and lipid production capabilities.
Dunaliella tertiolecta has the highest lipid productivity at 35.6%.
Nannochloropsis sp. ranges between 31-68% for lipid content.
Schizochytrium sp. demonstrates significant lipid productivity, ranging from 50-77%.
Others like Spirulina platensis and Scenedesmus dimorphus show lower ranges of 4-14%.

Microalgae and Cyanobacteria in Biotechnology

Microalgae and cyanobacteria can achieve oil productivity levels surpassing those of traditional agricultural crops.
They can grow in aquatic media and non-cultivable land, making them versatile for biofuel production.
Challenges in this field include high operating costs, biomass productivity concerns, process stability in outdoor conditions, and extensive water use.

Lipid Biosynthesis and Storage

Lipid accumulation is facilitated via the packaging of triacylglycerols (TAGs) into lipid droplets within cells.
Certain strains showed high growth and lipid production rates at elevated temperatures (40 °C).
The lipid biosynthesis pathway details the conversion and accumulation mechanics in microalgal cells.

Cultivation Strategies

Two-stage cultivation is emphasized: a nutrient-replete stage for biomass production followed by a nutrient-limited stage to trigger lipid accumulation.
Pilot scale production transitions from laboratory flasks to larger photobioreactors for scaling efficiency.

Carbon Partitioning

Microalgae can utilize carbon from various sources: atmospheric CO2, industrial exhaust gases, or soluble carbonate forms.
Carbon source impacts the decoupling of biomass production and lipid accumulation.

Experimental Design Considerations

The growth and lipid content of microalgae were measured during experiments involving various strains under controlled conditions.
Parameters monitored include optical density, cell count, neutral lipids concentration, temperature, and light intensity.

Nitrogen Starvation Impact

Effects of nitrogen deprivation (NaNO3) were studied over 18 days, revealing only four strains survived the nutrient limitations and exhibited enhanced lipid accumulation.
Experimentation utilized BG11 media with 1% NaCl.

Extraction and Yield of Lipids

Desmodesmus intermedius yielded 14 g of neutral lipids from every 100 g of biomass, equating to 14% lipid content.
Synechocystis sp.PCC 6803 achieved a similar yield of 13.5% neutral lipids.
The lipid extraction process often involves solvent methods, such as using hexane followed by rotary evaporation to isolate lipids effectively.

Biodiesel Production Insights

The conversion of lipids extracted from microalgae into fatty acid methyl esters (FAME) is a crucial step in biodiesel formation, as indicated by the 18.2 g of FAME yield from Desmodesmus intermedius lipids.

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Description

Test your knowledge on various species of microalgae, including Dunaliella, Isochrysis, and Spirulina. This quiz will challenge your understanding of their characteristics and classifications. Perfect for students of biology or anyone interested in marine life!