Biofuel production: tapping into microalgae despite challenges

Abstract

8Biofuels provided 2.7% of world's transportation fuel in 2015 which is expected to go up to 9 28% by 2050. However, most of the biofuel produced till date is from crops that can be used 10 as food or feed. Microalgae or most famously the 3 rd generation of biomass has the potential 11to overcome the problems associated with this food vs fuel debate. Microalgae are microscopic 12 photosynthetic organisms which have the ability to fix CO2. Thermochemical conversion via 13 hydrothermal liquefaction is a favourable technology for recovering energy from algal 14 biomass. Research is focused on discovering a viable and sustainable feedstock by cultivating 15and up-scaling the use of microalgae and then utilizing hydrothermal liquefaction to produce a 16 workable biofuel. Synthetic biology and several genetic engineering techniques have also 17shown promising results in the production of biofuels. Plenty of research is being carried out 18 in the field of using microalgae as biomass for biofuel generation; however, it still calls for a 19 robust conversion technology to make the process commercially viable. 20 21 22 23

A Hybrid Flux Balance Analysis and Machine Learning Pipeline Elucidates Metabolic Adaptation in Cyanobacteria

“…Synthetic biologists have been successful in assembling genetic material and manipulating the lipid content of microalgae, as well as maximizing biomass accumulation and biofuel yield (Jagadevan et al, 2018). These results are promising for the biofuels industry from the microalgal perspective (Randhawa et al, 2017). In the context of microalgae, the alteration of lipid iScience Article biosynthesis pathways through the induction of a stress response to a change in environment (such as temperature, nutrient limitation, salinity) is a common practice to enhance the production of target compounds, including those that are used to produce workable biofuels (Rawat et al, 2013).…”

“…Through the understanding of transcription levels and gene activation data gathered from transcriptomics, the effectiveness of genetic alterations can be measured as previously achieved for other organisms, allowing for optimization of the target product. For example, if the new gene insert is operating at its optimum, the transcriptomic data should show an increase in the mRNA of the target gene when compared with the wild type (Randhawa et al, 2017). Based on genomic and transcriptomic data, Wang et al (2019) recently identified a series of neutral sites on the chromosome of Synechococcus sp.…”

“…The application of omic studies can not only ascertain the effectiveness of any genetic modification but also be used to optimize the scale-up process. With the use of spatial and temporal omics studies of systems such as raceways used for algal growth, a deeper understanding of how algae will perform in various areas of the raceway can be gained, allowing for process optimization ( Randhawa et al., 2017 ).…”

Tailoring Microalgae for Efficient Biofuel Production

“…The study concluded that the outdoor culturing of GM microalgae fails to affect the microalgal diversity in the native ecosystem. However, before drawing any conclusion, extensive studies should be conducted as it is evident that regulatory certainty would be critical in the development of economically viable processes for algaebased biofuel production (Glass, 2015;Randhawa et al, 2017). Recent success in technology demonstration of biojet fuel is a sign of emerging prospects of microalgal biofuel for commercial ignition (Siobhan, 2010;Gyekye, 2017;Chandra, 2018).…”

Photosynthetic efficiency in microalgal lipid production

“…Alternatively, the availability of more than 20 whole algal genomes and recent developments in molecular toolboxes allows for (targeted) genetic engineering strategies to improve (lipid) metabolism (Hamed, 2016;Radakovits et al, 2010;Randhawa et al, 2017). Although many attempts were made, only a few studies resulted in strains with improved TAG productivities (Table 6.1).…”