Using Microalgae for Biofuel production

 

Emission of greenhouse gases, due to incomplete combustion of fuel while riding on a car, results in Global warming. This has led to melting of glaciers, causing rise in sea level. Furthermore, deforestation among regions has contributed further. Moreover, fossil fuels will be depleted because it cannot be recycled. On the contrary, renewable fuels are more efficient, as they are having oxygen molecules, facilitating for complete combustion of the fuel and thereby, reduces the emission of gases, such as Carbon Monoxide, which makes such fuel environmentally friendly. 

Now that, due to the current outbreak of COVID-19, we all are recommended to keep social distancing, maintain hand washing protocols and most important, observe self-isolation as the government has claimed for complete lockdown, about two months before. Due to such situations, when, apart from healthcare workers and few other offices, each person was obliged to stay at home. Meaning, most work was performed through online, students have to resume their studies, online, and as mentioned, the longer the person stays at home, the more the consumption of electricity they consume, unlike our perception, as we think of it as an opposite (Broto & Krishner, 2020).

Also, due to the sudden rise of incident cases, worldwide, the need for persistent and lots of electricity was required. From the telemedicine to diagnosis to ICU, all steps require power consumption. The widespread use of COVID-19 among our community has led to screening and diagnosis of each suspect and does need power to operate equipment, such as to run PCR machines. Ventilators are electrical operations that are applied on patients with severe respiratory conditions (Broto & Krishner, 2020). In certain countries, like Senegal, where healthcare institutes don’t have facilities to power source and thus, depending on renewable sources (Broto & Krishner, 2020). 

 Countries, where their people don’t have access to electricity, rely on coals for  cooking and are susceptible to COVID-19 and other diseases, like cancers, due to daily exposure to smoke (Broto & Krishner, 2020). Also, with gradual growth of population, globally, the demand of electricity has increased (Raheem et. al, 2018).

Knowing so many benefits of electricity during such conditions, by the end of April, this year, the sudden fall  of oil price, in history, has impacted the economy, worldwide, due to less demand of oil, than its supply. Vehicles were banned. Restriction of travelling foreign countries was implemented and therefore, no flights were arranged for months.

Oil companies, especially in Indonesia, Malaysia and Brazil, which was based on biofuel are now closed. In Brazil, people in rural area were part of this contribution and due to closure of biofuel industries, most people in rural area are now unemployed.

Biofuel has advantage to certain renewable resources, like that of solar energy, which depends on climate and geographic location.
Biofuel, mainly comprises of lipid constituents and alcohol moiety, that are extracted from plant and microalgae.The most common types of biofuels are: 1) First Generation biofuel, which depends on edible plants,like apricots and almonds, and 2) Second Generation biofuel, which depends on non edible parts of plants, such as agricultural wastes (Raheem et. al, 2018).

The two examples, as mentioned, are mostly based on plant biomasses, with the former depending on cellular constituents of cells and the latter depending on cellulose within the cell wall of plant biomass, like sugarcane bagasse.

 Apart from these two, two other kinds have been discussed in papers are: 1) Third-generation biofuel, produced by microalgae, and; 2) Fourth-generation biofuel, produced by microalgae after modification of genome (Raheem et. al, 2018).

 The advantage of such ways of producing biofuel is due to rapid growth and easy adaptation to its environment (Raheem et. al, 2018). They are not dependent on soil or climate, in contrast to plants and can be bred on seawater or wastewater (Raheem et. al, 2018). Furthermore, they are rich in lipids, as compared to plants, especially of Jatropha (if algae are given optimal temperature) (Raheem et. al, 2018). The proportion

of constituents within algae biomass, rely on what parameters are they provided with for growth.

The procedure for biofuel production requires:

1. Bioprocessing: A stage where algae are cultured, providing them with certain parameters. The lipid accumulates inside an algae when the cell faces stress conditions, for instance, a limited amount of nutrients (Jagadevan et. al., 2018). A study reported of accumulation of lipids, along with increase in multitrophic algal biomass, when fermented in fed-batch cultures (Jagadevan et. al., 2018). In contrast, heterotrophic algae have not been able to produce sufficient lipids. So, if an algal cell faces stress conditions, it generates a bulk amount of lipids. Furthermore, by culturing algae on plant biomass as the source of material, bacteria or fungus can be co cultured with the algae. Being in a symbiotic relationship, bacteria or fungus could aid algal cells by facilitating digestion of lignocellulose within plant biomass  (Raheem et. al, 2018).
2. Harvesting: After culturing algal cells for biofuel products, this is not the end. Afterwards, extracting cellular constituents for intermediates , to make it to use. Extracting oil can be performed, either by 

a)     Thermochemical means, when intensive heat and chemical usage, breaks cells to expose cellular constituents. To further classify:

                                      i)        Pyrolysis: Algal biomass is treated in an environment of temperature of 300 to 700 Celsius, without air, to break out cells (Raheem et. al, 2018).

 

                                      i)        Gasification: The biomass is treated with more than 700 Celsius with a measurable amount of Oxygen pressure to realize biofuel gas (Raheem et. al, 2018).

b)    Biochemical means: Oil constituents are released from algal biomass after treating with either a microorganism or enzymes (Raheem et. al, 2018).

       

                                      i)        Gasification: The biomass is treated with more than 700 Celsius with a measurable amount of Oxygen pressure to realize biofuel gas (Raheem et. al, 2018).

b)    Biochemical means: Oil constituents are released from algal biomass after treating with either a microorganism or enzymes (Raheem et. al, 2018).

3)     Fermentation: After extraction of biofuel intermediates, the extract is further proceeded for fermentation, to produce 1) Biogas, examples including, Methanes, and; 2) Biodiesel, liquid form of fluid, usually consisting of Butanol (Raheem et. al, 2018).

 

Another way to produce lipid components for biofuel production is through engineering microalgae, either by Genetic engineering or through Synthetic Biology. The benefit of using engineered algae for biofuel production is that it could resist accumulation of wastes, as microalgae generates lipids (Jagadevan et. al., 2018). The gene or the biological system can be rewired to resist against their waste and sustain their growth, at maximum.

 As in Genetic Engineering, a desirable gene is cut from one strain and implanted in another strain to efficiently produce lipids (Jagadevan et. al., 2018). Note that the gene is transferred within species, otherwise,it might disrupt function, as each species has different characteristics to adapt to a certain environment. Engineering microalgae could either overexpress enzymes that take part in lipid synthesis or lower expression of those which degrades lipids (Jagadevan et. al., 2018).

 In contrast, Synthetic Biology encompassed across, as it’s not dependent on just genes, but also includes certain parts within the genome that are not coding regions (Jagadevan et. al., 2018). These portions includes, promotors, termination regions and even ribosome binding sites. Unlike genetic engineering, Synthetic Biology is based on ‘omics’ concept. Creating an artificial biological system might change cellular behavior, by responding to certain signals or inputs to give an output. Through certain modifications within the genome of chloroplasts, an algae may respond with the same intensity and frequency of light with increased rate of photosynthesis and thereby, more biomass formation (Jagadevan et. al., 2018). Also, modifying genomes could change the metabolic pathway by increasing flux of carbon source to produce lipid constituents. Also, these modifications can make microalgae robust to be cultured in cheap agricultural waste on a large scale to produce oil for biofuel production. The modification in ‘omic’ level can affect other metabolic pathways, as well, so as to channelize carbon sources to accumulate into lipids (Jagadevan et. al., 2018). Each system is complex and to engineer a biological system, the in silico or the tools of bioinformatics are must, from which we could analyse our predicted modification to get desirable results. It is not just to rely on the outcomes but also, what inputs are applied in order give such results (Jagadevan et. al., 2018). 

 So, to sum up, the latest techniques to accumulate lipids for biofuel production, are also applicable for other bioproducts. The use of Synthetic Biology and Bioinformatics has reduced errors that occured through Genetic engineering. The latter either affects expression of certain genes or another gene is added which changes the system (Jagadevan et. al., 2018). Synthetic Biology and Bioinformatics provided us with a new perception of looking cells as interacting systems, rather than just changing just one gene. Although, studies were conducted which did applied genetic engineering for biofuel production but it was reported as not being efficient like that of Synthetic Biology (Jagadevan et. al., 2018). Secondly, the biotechnological applications upon producing certain biofuel, differ from using the same strain to produce different bioproducts. The stress environment and mixotrophic characteristic of microalgal within a bioreactor to produce, will vary depending on the nature of the bioproduct. If we are aiming for protein products, then such parameters would change to produce proteins.

 The application of microalgae as a source for biofuel production can be beneficial for Pakistan’s economy, as of news updating locust swarm, raiding and eating up the whole crop field in Pakistan. Resulting the loss of the economy, as our country depends on agriculture for its development. Moreover, it has been reported that biogas has been an effective renewable source among villages of Pakistan but insufficient to sustain the whole village (Uddin et. al, 2016). 

References:

1. Broto, V. C., & Kirshner, J. (2020). Energy access is needed to maintain health during pandemics. Nature Energy, 1-3.
2. Jagadevan, S., Banerjee, A., Banerjee, C., Guria, C., Tiwari, R., Baweja, M., & Shukla, P. (2018). Recent developments in synthetic biology and metabolic engineering in microalgae towards biofuel production. Biotechnology for biofuels, 11(1), 185.
3. Uddin, W., Khan, B., Shaukat, N., Majid, M., Mujtaba, G., Mehmood, A., ... & Almeshal, A. M. (2016). Biogas potential for electric power generation in Pakistan: A survey. Renewable and sustainable energy reviews, 54, 25-33.
4. Raheem, A., Prinsen, P., Vuppaladadiyam, A. K., Zhao, M., & Luque, R. (2018). A review on sustainable microalgae based biofuel and bioenergy production: Recent developments. Journal of cleaner production, 181, 42-59.

By:  Mohammad Irtaza Tafheem