Recent Advances in Enzymatic Conversion of Microalgal Lipids into Biodiesel

Abstract

The use of microalgae to produce biodiesel is a beneficial and green substitute for conventional fossil fuels (a major source of greenhouse gas emissions). Microalgae have several merits, including their nontoxic nature, fast growth rate, growth not being dependent on the supply of fresh water, potential for biodegradability, and not requiring arable land for their growth. The exploration of novel frontiers to establish large-scale operations is vital for economically feasible biodiesel production, taking advantage of these favorable attributes. This review is focused on the recent development of the enzymatic transformation of microalgal oils into biodiesel. The areas addressed in this work include (i) microalgae and their lipid content, (ii) maximization of lipid productivity and lipid extraction, (iii) biodiesel production by enzymatic transesterification, (iv) enzyme kinetics, (v) factors affecting enzymatic transesterification, and (vi) immobilized enzymes and their limitations. In addition, various aspects of free enzyme and its potential future applications are discussed. This review also highlights a number of strategies using ionic liquids (ILs) for the successful production of microalgal biodiesel. The present study suggests that free enzyme has a greater potential than immobilized enzyme for the transesterification of bio-oils containing phospholipids into biodiesel.

Locally Sustainable Biodiesel Production from Waste Cooking Oil and Grease Using a Deep Eutectic Solvent: Characterization, Thermal Properties, and Blend Performance

“…The other major features in the spectrum correspond to water, the combustion gas partner of CO 2 , with the H 2 O asymmetric stretch at 3754 cm –1 , the symmetric stretch at 3655 cm –1 , and the broad bending–rotation band at 1594 cm –1 . In addition to CO 2 and H 2 O, the spectrum also shows a low-intensity CO rotation–vibration band at 2143 cm –1 with the inset showing the distinct rotation–vibration signature of heteronuclear diatomic CO . There is no ester CO stretching mode at 1743 cm –1 and only very slightest intensity of C–H alkane and alkene stretching modes from 2800 to 3200 cm –1 and CH 4 modes at 3030 cm –1 , indicating virtually complete combustion of the B30 in the generator to CO 2 and H 2 O with insignificant amounts of other combustion products.…”

“…Biodiesel is a sustainable alternative to petroleum diesel fuel, especially when using feedstock from nonedible oils that do not compete with food production, which is particularly important in developing economies . To increase production capacity from nonedible feedstocks, there has been much work recently on enzymatic conversion of sea-borne algae into biodiesel . Nevertheless, investigations continue in more traditional approaches using transesterification of triglycerides, from either pure oils or waste cooking oil and grease, into fatty acid methyl/ethyl esters. − The generation of glycerol-based byproducts of transesterification synthesis is problematic, as these byproducts often require additional resources and further processing to become useful materials rather than waste needing disposal, all of which increases costs and reduces sustainability aspects of biodiesel …”

How to Build a Microplastics‐Free Environment: Strategies for Microplastics Degradation and Plastics Recycling

“…For instance, natural or modified enzymes and microorganisms have been widely used for the application of biomass conversion, nitrogen fixation and water treatment. [212][213][214][215] The intake and metabolism of pollutants by microorganism or directly interaction between pollutants and extracellular enzyme of microorganism give rise to the mineralization or transformation of hazardous pollutants into CO 2 , H 2 O, or other non-toxic small organic molecules. [22] With the merits of good efficiency, low operating cost, and no secondary pollution, controlling the pollutants in environment by biotechnology is undoubtedly a development trend in the future.…”

Cultivation and Processing of Microalgae for Its Sustainability as a Feedstock for Biodiesel Production

“…The use of enzymes as catalysts for biodiesel production from microalgae lipids is gaining wide acceptance due to its economic feasibility and being environmentally benign which eliminates the adverse effects of chemical catalysts (Hossain et al, 2020). Also, the enzymatic transesterification of triglycerides has a high-purity biodiesel yield, no side reaction, reduced operational cost, easy separation, it is recyclable and has no alkaline wastewater.…”

“…Also, the enzymatic transesterification of triglycerides has a high-purity biodiesel yield, no side reaction, reduced operational cost, easy separation, it is recyclable and has no alkaline wastewater. These advantages indicate that enzymatic transesterification is the most suitable among other catalysts, for sustainable biodiesel production (Hossain et al, 2020;Wang et al, 2014).…”