Reactive extraction and in situ self-catalyzed methanolysis of germinated oilseed for biodiesel production

Abstract

Compared with conventional production of biodiesel from oilseeds, in situ reactive extraction of oilseeds with acyl acceptors is an attractive approach, which consists of sustainable, economically attractive biotechnological processes for biodiesel synthesis. In this study, the presence of lipase activity in germinating oilseeds was detected and the lipase activity increased to a maximum after 4 days of germination. At that time, the germinated seeds featured an only slightly lower oil content relative to the ungerminated seeds. As such, an environmentally friendly and low-cost in situ self-catalytic process for biodiesel production was developed. The biodiesel was prepared by reactive extraction of germinated Jatropha curcas L. seeds with methanol without any other catalyst added. In this process, nhexane was used as reactive extraction solvent. The highest fatty acid methyl esters (FAMEs) yield of 87.6% could be achieved under the optimum conditions: a n-hexane/germinated seed ratio of 2.5 ml g À1 , a methanol/germinated seed oil (contained approximately 90% FFA) molar ratio of 1.5 : 1, a reaction temperature of 35 C, a germinated seed water content of 2.9% and a reaction time of 8 h. This simple reactive extraction process without additional catalyst can be a potential route for biodiesel production, which may greatly reduce the processing steps and costs.

In situ transesterification of Jatropha curcas L. seeds in subcritical solvent system

“…Moisture and FFA contents in feedstock oil are usually kept below 1% to avoid side reactions in conventional processes. Seeds should be kept dry to avoid germination, in which hydrolysis of storage lipids and consumption of lipids in post germination occur causing a decrease in extractable lipids [18]. To avoid this, seeds were dehulled, ground and kept dry in this study.…”

“…From Table 5 it can be seen that SSR used in this study is lower than most nonsupercritical processes reported in literature utilizing acid and base catalyst, requiring an SSR of between 7.5 ml/g and 10.5 ml/g [23][24][25][26], except for the self-catalyzed methanolysis utilizing indigenous lipase to self-catalyze the reaction. Although the self-catalyzed reaction used a lower SSR, it required a 4-day germination period [18]. The germination period varies depending on seed strain and activity of the indigenous lipase.…”

Fatty acid ethyl esters production in aqueous phase by the oleaginous yeast Rhodosporidium toruloides

“…FAEEs production catalyzed by R. toruloides Y4 cell homogenates R. toruloides Y4 cells from 6 mL of lipid-rich culture were lyophilized, milled to powder and extracted by cold acetone (Gu et al, 2011). Extracts and cell residues were mixed again, dried by N 2 , and then resuspended with 6 mL of deionized water.…”

Strategies of preserving lipids in microorganism after fermentation

“…However, before lipid droplets are consumed, they would be firstly hydrolyzed into FFA. And the enzymes (lipases) related to lipid metabolism may keep alive in the conditions that the cells are inactivated (Gu et al, 2011;Jin et al, 2013). The hydrolysate, especially free fatty acids, can deeply affect the selection of catalysts in the process (transesterification) to produce biodiesel and biodiesel yield (Atadashi et al, 2012).…”