1 - Fundamentals of microalgae-based processes.

1.7 - Self-assessment: questions and problems

- Questions

1. List the advantages of microalgae over higher plants. What are the main nutrients required for microalgae cultivation?

2. What is PAR radiation? How does it differ from total radiation? How can quantum measurements $(\mu E/m^2 \cdot s)$ be converted to energy measurements $(W/m^2)$?

3. How much $O_2$ is released during the generation of 1 kg of biomass? (Assume $x_C = 0.5$.)

4. How much $CO_2$ is consumed to release $1\, m^3$ of $O_2$ at standard conditions? How many photons would be absorbed in the above question?

5. Define productivity and specific growth rate. Explain whether there is a relationship between the two parameters.

6. What are the units of $\mu$? And of $P_b$? Comment on why this is so.

7. How would you calculate $\mu$ from $C_b$ vs. time data? Could you use decimal logarithms in the process?

8. What is a nutrient saturation situation? What happens under light limitation? Is it advisable to eliminate light limitation at all costs in PBR design?

9. Make an ordered list of the types of PBRs mentioned in this lesson.

10. Compare the advantages and disadvantages of open PBRs versus closed PBRs.

- Interactive questions

Why do microalgae grow faster than higher plants and macroalgae?

Because they are microorganisms

Because their doubling time is shorter

Because they adapt better to the environment

Because they only need light to grow

Microalgae do not necessarily grow faster than higher plants

Select the most correct statement:

All microalgae are photoautotrophic

Microalgae and cyanobacteria belong to the same photosynthetic family

The photosynthetic efficiency of microalgae is greater than that of higher plants

Microalgae do not need any external carbon source

We say that photosynthesis is a quantum process because:

The energy of the photon does not matter as long as it is PAR

More energetic photons (shorter wavelength) produce more intense photosynthesis

The capture of photons by PSUs is a process governed by quantum mechanics

The number of photons needed to fix one inorganic carbon atom is indeterminate

What is the value of $\Psi_{CO_2/b}$ when the nitrogen source is potassium nitrate?

What is the energy of a 550 nm photon in kJ/mol?

Question 1: What is the Beer-Lambert equation?

I = I₀ · e^(-k·C·x)

I = I₀ · k · C · x

I = I₀ / (k·C·x)

I = I₀ + k·C·x

Using the basic photosynthesis equation, how many grams of water are consumed to fix 1 kg of $CO_2$?

Select the most correct statement:

Bubble columns are the easiest photobioreactors to scale up

Tubular photobioreactors are stable, easy to build and cheap

Raceways are the most suitable photobioreactors for sensitive, slow-growing species

Thin-layer photobioreactors produce high-quality biomass but their productivity is low

Open-type photobioreactors are suitable for low-value products