Variability of Omega-3/6 Fatty Acid Obtained Through Extraction-Transesterification Processes from Phaeodactylum tricornutum

The effect of direct transesterification methods on the omega-3/6 composition of extracts from Phaeodactylum tricornutum was studied. The aim of this work was to identify an extraction method which allowed to obtain the most suitable profile of fatty acids in terms of its potential benefits to health, particularly if further used in the food industry. Seven methods using acids, alkalis, and heterogeneous-catalysts, (namely methods from 1 to 7, abbreviated as M1-M7) were performed to determine α-linolenic (ALA), linoleic (LA), docosahexaenoic (DHA) and eicosapentaenoic (EPA) acids. The composition of fatty acids was in all cases characterized by the major abundance of palmitic (23.95–34.08%), palmitoleic (30.94–35.56%), oleic acids (3.00–7.41%), and EPA (0.5–6.45%). Unsaturated fatty acids extraction yield was higher with a two-step transesterification process (M6, 63.65%). The total fatty acid methyl ester content (FAME) obtained with acid-transesterification (M1) reached about 21% wt, and 60% w/w total lipids. ALA higher relative content (ALA/LA ratio) was obtained when a lipid pre-extraction step was performed prior to acid-catalysis (M4). The transesterification method based on alkali-catalyst (M3, KOH catalyst) led to obtain higher DHA relative contents (DHA/EPA ratio up to 0.11), although its FAME content was 3.75-fold lower than that obtained with acid-transesterification (M1). Overall, this study shows that direct transesterification with alkali-catalyst (M3) improves the determination of PUFA content from the diatom through a more efficient transesterification-based extraction process, and thus allow to assess the value of the biomass more accurately for application in the food industry.

Synthesis of Poly(Ethylene 2,5-Furanoate): I. Kinetics of 2,5-Dimethyl Ester of Furandicarboxylic Acid Transesterification

The kinetics of the 2,5-dimethyl ester of furandicarboxylic acid transesterification in the presence of various catalysts at different temperatures was investigated. It was shown that the catalytic activity follows the order: Mn (OAc)2 < Co (OAc)2 < Zn (OAc)2 < Ti (OBu)4. The transesterification catalyzed by Ti (OBu)4 leads to the formation of the polymers with the higher molecular weight compared to Me (OAc)2.

Continuous Flow Esterification of a H-Phosphinic Acid, and Transesterification of H-Phosphinates and H-Phosphonates under Microwave Conditions

The microwave (MW)-assisted direct esterification of phenyl-H-phosphinic acid, transesterification of the alkyl phenyl-H-phosphinates so obtained, and the similar reaction of dibenzyl phosphite (DBP) were investigated in detail, and the batch accomplishments were translated into a continuous flow operation that, after optimization of the parameters, such as temperature and flow rate, proved to be more productive. Alcoholysis of DBP is a two-step process involving an intermediate phosphite with two different alkoxy groups. The latter species are of synthetic interest, as precursors for optically active reagents.

Biomass Production and Ester Synthesis byIn SituTransesterification/Esterification Using the MicroalgaSpirulina platensis

The increasing energy demand and reduction in the availability of nonrenewable energy sources, allied with an increase in public environmental awareness, have stimulated a search for alternative energy sources. The present study was aimed at producing biomass from the microalgaSpirulina platensisand at assessingin situsynthesis of alkyl esters via acid transesterification/esterification of biomass to produce biodiesel. Two alcohols (ethanol and methanol) and two cosolvents (hexane and chloroform) were tested, at different temperatures (30, 45, 60, 75, and 90°C) and reaction times (10, 20, 30, 60, and 120 min). The factorial analysis of variance detected an interaction between the factors (): temperature, reaction time, alcohol, and cosolvent. The best yields were obtained with the combination ethanol and chloroform at 60°C, after 30 min of reaction, and with hexane at 45°C, after 10 min of reaction.In situtransesterification/esterification of alga biomass to form esters for biodiesel production adds unconventional dynamics to the use of this feedstock.