Improving ‘lipid productivity’ in microalgae by bilateral enhancement of biomass and lipid contents: A review

© 2020 by the authors. Licensee MDPI, Basel, Switzerland. Microalgae have received widespread interest owing to their potential in biofuel production. However, economical microalgal biomass production is conditioned by enhancing the lipid accumulation without decreasing growth rate or by increasing both simultaneously. While extensive investigation has been performed on promoting the economic feasibility of microalgal-based biofuel production that aims to increase the productivity of microalgae species, only a handful of them deal with increasing lipid productivity (based on lipid contents and growth rate) in the feedstock production process. The purpose of this review is to provide an overview of the recent advances and novel approaches in promoting lipid productivity (depends on biomass and lipid contents) in feedstock production from strain selection to after-harvesting stages. The current study comprises two parts. In the first part, bilateral improving biomass/lipid production will be investigated in upstream measures, including strain selection, genetic engineering, and cultivation stages. In the second part, the enhancement of lipid productivity will be discussed in the downstream measure included in the harvesting and after-harvesting stages. An integrated approach involving the strategies for increasing lipid productivity in up-and down-stream measures can be a breakthrough approach that would promote the commercialization of market-driven microalgae-derived biofuel production

Critical review on third generation micro algae biodiesel production and its feasibility as future bioenergy for IC engine applications

Third generation micro algae feedstock cultivation and fuel production have sustainable and economic benefits due to their microscopic nature. Each process in the production of micro algae biodiesel such as cultivation, harvesting and extraction can be optimized to negate the factors affecting production. Optimized micro algae biodiesel blends can be utilized to obtain ideal engine maps by calibrating engine parameters at stationary or dynamic engine tests. Numerous studies are available on micro algae based biodiesel production and its application in IC engines. Even though few consolidated articles are available on the effects of using micro algae biodiesel in IC engines, little to no article is available clubbing the production and optimization aspects of micro algae biodiesel with engine testing. To address this issue, this article intends to consolidate studies which have utilized different reactors for cultivating diverse micro algae species with multiple growth mediums. Furthermore, this combination also includes different biomass preprocessing and extraction techniques in producing micro algae biodiesel. Also, the implementation of micro algae biodiesel in IC engines and its output characteristics for different micro algae biodiesels have been highlighted and analyzed. To understand the current commercial status of micro algae biodiesel, a techno-economic analysis has been drawn. Studies revealed that closed type reactors are effective for continuous cultivation due to the constant regulation and availability of optimized growth factors. Furthermore, the techno-economic assessment revealed that the maintenance costs involved in the production should be lowered by 2–3 times the original to make micro algae biodiesel commercially available

Enzymatic hydrolysis using ultrasound for bioethanol production from durian (durio zibethinus) seeds as potential bio fuel

The appealing second generation bioethanol production brings a good promise to achieve a fuel production that is renewable and sustainable; this makes durian (Durio zibethinus) seed interesting to take advantage of, especially for a tropical country like Malaysia. This paper aims to produce bioethanol from durian seed by utilizing ultrasound technique in its enzymatic hydrolysis process. 9 % (w/v) pre-Treated durian seed was brought into the ultrasound-Assisted glass reactor to begin the liquefaction and saccharification processes. Bacillus licheniformis Type XII-A was employed, and ultrasound at 50% amplitude for 60 min was set for liquefaction process; while amyloglucosidase from Aspergillus niger was used, and ultrasound at 40% amplitude for 120 min was run for saccharification process. The sum of both processes in hydrolysis yielded 41.07 g/L of reducing sugar, which was immediately brought to fermentation stage. Saccharomyces cerevisiae was employed for fermentation and resulted 18.48 g/L (0.44 g ethanol/g glucose), which is equivalent to 86.27 % of theoretical ethanol yield (0.51 g ethanol/g glucose) after 84 h of fermentation at 37 °C with 150 rpm incubator shaker. The ethanol purity was improved in the next stage, distillation. Using zeolite as adsorbent, ethanol with purity of 95.7% (v/v) was produced. From the acquired results, durian seed shows a justifiably potential as a second generation bioethanol feedstock. To further improve its potential, studies of optimization using this feedstock is highly encouraged

Comparative assessment of hexanol and decanol as oxygenated additives with calophyllum inophyllum biodiesel

© 2019 Elsevier Ltd In this research work, the four ternary blends were prepared with 30% and 40% by volume of higher alcohol (decanol and hexanol) with biodiesel while maintain 50% of diesel concentration. All ternary blends of diesel-biodiesel-higher alcohols were used in single cylinder engine and the results were compared with binary blend of 50%–50% biodiesel, pure diesel and biodiesel. It was revealed that thermal efficiency of ternary blends was higher than biodiesel and in some cases it is closer to pure diesel. In contrary, specific fuel consumption is found to lower with increase in alcohol fractions in ternary blends. Moreover, hydrocarbon, smoke, carbon monoxide emissions from alcohol-infused fuel blends were observed to be lower than both biodiesel and pure diesel. Significant reduction in oxides of nitrogen (NOx) emissions was also observed by the addition of higher alcohols to the fuel blend when compared to biodiesel fuel. It is to be noted that decanol 40% addition with diesel and biodiesel blend has shown better results in emission characteristics. Furthermore, the heat release rate and in-cylinder pressure for biodiesel were significantly lower compared to pure diesel fuels. However, addition of 40% decanol with fuel blend improved the heat release rate and in-cylinder pressure

Sustainability of Palm Biodiesel in Transportation: a Review on Biofuel Standard, Policy and International Collaboration Between Malaysia and Colombia.

Biodiesel is gaining prominence as a superior alternative source of energy to replace petroleum-based fuel in transportation. As of today, the biodiesel market continuous to rise up as the biofuel has been introduced to more than 60 countries worldwide. The aim of the present review is to highlight on the scenario of the biofuel implementation in transportation sector towards sustainable development in Colombia and Malaysia. Colombia serves as an ideal comparative case for Malaysia in terms of biodiesel development since the country is the main palm oil producer in Latin America region and the pioneer in bioethanol industry. The first section shows an overview on the biodiesel as an alternative fuel in transportation. The next section will focus on a comparative study between Malaysia and Colombia biodiesel sector in terms of energy supply, resource, production and consumption, standards, techno-economic cost and their biodiesel policies. A comprehensive review was studied to discuss on the sustainability of palm cultivation and biodiesel, impact of palm industry and biodiesel policy in transportation sector and potential international collaboration between Malaysia and Colombia to improve their existing policies, strategies and blueprints related to the palm biodiesel industry, thus overcoming the challenges when dealing with global energy issue

Multi-functional fuel additive as a combustion catalyst for diesel and biodiesel in CI engine characteristics

© 2020 Elsevier Ltd The present research work aims at investigating the effect of newly developed multifunctional additive with diesel and Calophyllum Inophyllum biodiesel on compression ignition engine characteristics. A newly developed hydrocarbon based multifunctional fuel additive named as “Thermol-D” which comprises of various ingredients at suitable composition like surfactant, demulsifier, lubricity enhancer, dispersant, cetane improver, antioxidant and combustion catalyst. In this present study, the Thermol-D has been doped with conventional diesel and Calophyllum Inophyllum biodiesel at 0.5 ml, 1 ml and 2 ml concentrations. Moreover, the Thermol-D addition with diesel and biodiesel has shown remarkable stability at all concentrations without any phase separation issues. All the fuel comparative analysis is carried out using all the fuel samples at same operating conditions under load variation from No load to full load at constant engine speed. It has been noticed that the doping of Thermol-D with diesel and biodiesel has increased the brake thermal efficiency by 21% and 43% at 100% loading conditions due to the presence of combustion catalyst and cetane improver in the additive. The multifunctional additive presence in the fuel blends is reduced the carbon monoxide and unburnt hydrocarbon emissions by 32–36% and 20% respectively. Furthermore, the oxides of nitrogen emission has also reduced at significant rate in the range of 18–20.5% for 2% Thermol-D addition with diesel and biodiesel. The Thermol-D contains slight fraction of antioxidant and cetane improvers which has resulted in combustion temperature. All the combustion characteristics are improved by the addition of Thermol-D with diesel and biodiesel