Enzymatic synthesis of epoxy fatty acid starch ester in ionic liquid–organic solvent mixture from vernonia oil

Abstract

In this study, epoxy fatty acid esters of cassava starch were synthesized by reacting cassava starch with vernonia oil methyl ester (epoxy ester) using 1-butyl-3-methylimidazolium hexafluorophosphate, [C 4 C 1 Im][PF 6 ] ionic liquid (IL) as a reaction medium and DMSO as co-solvent. Lipase Candida antarctica fraction B (Novozyme 435) was used as a catalyst for the esterification reaction. In the optimized reaction conditions, a degree of substitution (DS) of 0.95 was achieved, at a reaction temperature of 40°C within 72 h of reaction time. The new cassava starch esters were characterized by infrared (FTIR), solid state NMR (CP/MAS 13 C NMR), SEM, XRD, thermogravimetric analysis (TGA), and DSC. FTIR and NMR spectroscopy analyses confirmed the successful esterification of starch and the DS was calculated to be 0.95 by titration methods. SEM and XRD studies showed that the morphology and crystallinity of native cassava starch were significantly changed upon esterification producing a continuous and amorphous material. Finally, the thermal behavior of the native and the starch vernolate was investigated using TGA and DSC techniques. The results revealed a change in the characteristic melting point and decomposition pattern of the new polymer. The onset decomposition temperature of the new starch vernolate is similar to the native form.

Synthesis and Characterization of Starch Vernolates in Organic Solvents

“…The product and the starting materials exhibited different solubility trends which confirm that a new product has been synthesized. The insolubility of the product indicates that the new material is water proof and also resistant to many different organic solvents [1,50].…”

“…The use of renewable raw materials in the chemicals industry for non-fuel applications offers enormous opportunity to establish a more sustainable development profile, enabling society to meet the needs of current and future generations whilst minimizing future environmental degradation [1]. Recently, plant oils and naturally occurring triglycerides of fatty acids, are being studied as potential sources of renewable feedstocks for the oleochemical industry [2].…”

“…Vernolic acid offers potential application in the formulation of additives, coatings, and lubricant additives. Vernonia oil has become a unique renewable candidate for industrial feedstock due to its use as raw material and its potential derivatization into value-added products [1,[6][7][8][9].…”

“…Our group have recently reported the synthesis of epoxy fatty acid esters of cassava starch by reacting cassava starch with vernonia oil methyl ester (epoxy ester) using 1-butyl-3-methylimidazolium hexafluorophosphate, 6 ] ionic liquid (IL) as a reaction medium and DMSO as co-solvent [1]. Similarly we have also reported the successful preparation of epoxy fatty acid esters of cassava starch (starch vernolates) by reacting cassava starch with vernonia oil methyl ester using only 1-butyl-3-methylimidazolium chloride, [C 4 C 1 im]Cl, ionic liquid as a reaction medium and an inexpensive base such as pyridine as a catalyst [50].…”

A Green Process for Starch Oleate Synthesis by Cryptococcus sp. MTCC 5455 Lipase and Its Potential as an Emulsifying Agent

“…Lipase catalyzed enzymatic esterification of starch is an eco‐friendly process without producing chemical wastes . Moreover, the high selectivity (chiral, positional, and functional) of lipases is advantageous because it minimizes side reactions and allows easier separation of the products . There are reports available on synthesis of starch esters by commercial lipases from Burkholderia cepacia , Pseudomonas sp., Candida rugosa , Thermomyces lanuginosus , C. antartica , and porcine pancreas .…”