Virginija Skorupskaite

Biodiesel fuel from microalgae-promising alternative fuel for the future: a review

The use of organic matter such as vegetable oil to produce biodiesel fuel has been a practical technology for a number of years. However, the search for new technologies and raw materials for biodiesel fuel production has gained increased attention recently because of financial and environmental concerns. Of particular interest are raw materials that are not food-related. Microalgae have gained a great deal of attention as a potential biodiesel raw material because of their high growth rates and ability to accumulate oil, bind carbon dioxide, and remove contaminants from wastewater. This article is a literature review of technologies for biodiesel production from microalgae. The technologies relate to microalgal cultivation, microalgal growth enhancement to simultaneously increase biomass and reduce pollution, the preparation of microalgal biomass for biodiesel production, and biodiesel production itself.

The optimization of biodiesel fuel production from microalgae oil using response surface methodology.

Biodiesel fuel was produced by the transesterification of microalgae oil using sodium hydroxide as a catalyst. The oil was extracted from heterotrophic cultivated algae biomass. The transesterification process was optimized using response surface methodologyto increase the yield of methyl esters. The Box–Behnken design and fractional factorial design 24-1 points were used to investigate the interaction of process variables, such as the methanol/oil molar ratio, the percentage of sodium hydroxide, the temperature, and the reaction time in the production of biodiesel fuel, and to predict the optimum process conditions for the FAME yield. Based on the results, the optimal conditions for the synthesis of biodiesel fuel were as follows: methanol/oil molar ratio, 7:1; catalyst concentration, 1.0% (by weight of algae oil); temperature, 67°C, and reaction time, 51 minutes. The yield of FAME was confirmed by gas chromatography analysis.

Biodiesel fuel production by enzymatic microalgae oil transesterification with ethanol

This paper discusses the application of the enzymatic transesterification of algae oil with ethanol for the production of biodiesel fuel. Seven commercial lipases were tested, and the most effective lipase preparation—Lipolase 100L—was selected. The transesterification process was optimised by applying response surface methodology. The interaction of the molar ratio of ethanol to oil, the process duration, the lipase concentration, and the temperature was evaluated. Transesterification experiments were performed under different conditions, and the transesterification yield was measured. On the basis of the transesterification yield, a quadratic model was built, and the optimal conditions were determined: a temperature of 30 °C, a lipase amount of 10%, and an ethanol to oil molar ratio of 3:1. After 26 h, the transesterification yield was increased to 96.9%, and the requirements of the European standard for biodiesel fuel (EN 14214) were met.

Enzymatic microalgae oil transesterification with ethanol in mineral diesel fuel media

This article examines opportunities of enzyme application during the production of biodiesel from microalgae oil by its transesterification in the mixture with mineral diesel fuel. The oil and mineral diesel fuel ratio in the reaction mixture enabled a yield of 7% ester content in the mixture. Effectiveness tests were conducted on seven industrial lipases, and Lipozyme TL IM was selected as the most effective lipase for further optimization. The process of algae oil transesterification with ethanol was optimized by applying response surface methodology. The interactions and impacts of the following independent variables on the transesterification yield were evaluated: ethanol and oil molar ratio, process duration, lipase content, and temperature. Optimum conditions were determined: a temperature of 30 °C, 13.26% biocatalyst (from the oil content), an ethanol and oil molar ratio of 4.54:1, and a process duration of 13 h. The transesterification yield of the product under the above conditions reached 98%.