Methanol-tolerant lipase producing yeast was successfully isolated and selected thorough ecological screening using palm oil-rhodamine B agar as one step-approach. All 49 lipase-producing yeasts exhibited the ability to catalyze esterification reaction of oleic acid and methanol at 3 molar equivalents. However, only 16 isolates catalyzed transesterification reaction of refined palm oil and methanol. Rhodotorula mucilagenosa P11I89 isolated from oil contaminated soil showed the strongest hydrolytic lipase activity of 1.2U/ml against palm oil. The production of oleic methyl ester and fatty acid methyl ester (FAME) of 64.123 and 51.260% was obtained from esterification and transesterification reaction catalyzed by whole cell of R. mucilagenosa P11I89 in the presence of methanol at 3 molar equivalents against the substrates, respectively. FAME content increased dramatically to 83.29% when 6 molar equivalents of methanol were added. Application of the methanol-tolerant-lipase producing yeast as a whole cell biocatalyst was effectively resolved major technical obstacles in term of enzyme stability and high cost of lipase, leading to the feasibility of green biodiesel industrialization.
"Four factors including carbon (A), nitrogen (B), initial pH (C) and surfactant (D), as well as their types and levels displayed in Table 1 were first evaluated using Taguchi experimental design, operated in nine runs as shown in Table 2. As reported earlier, lipase hydrolysis was found to be irrelevant to the synthesis activities of esterification and transesterification (Srimhan et al. 2011). Therefore, two CBL catalytic characteristics of hydrolytic and synthetic activities were determined. "
[Show abstract][Hide abstract] ABSTRACT: Rhodotorula mucilaginosa P11I89, isolated from oil-contaminated soil, was effectively used as the methanol-tolerant, whole-cell lipase for the synthesis of fatty acid methyl ester (FAME) via transesterification reaction in the presence of palm oil and methanol substrates at a 1:6 mole ratio. A combination of Taguchi experimental design and response surface methodology (RSM) were applied to systemically enhance transesterification activity of the whole-cell lipase or cell-bound lipase (CBL) from R. mucilaginosa P11I89 in a solvent-free system. The significant impacts of four factors including carbon sources, nitrogen sources, surfactants and pH on hydrolysis activity of extracellular and cell-bound lipases, and on the transesterification activity of CBL were evaluated using Taguchi design. Gum Arabic was the most significant component for high transesterification activity, whereas soybean oil was the most influential factor for the hydrolysis activity. Maximal CBL production of 272.72 U/L was obtained in the cultivation medium containing 2.1 % palm oil, 0.2 % NH4NO3 , and 0.45 % Gum Arabic, with initial pH 5.0 under shaking speed of 200 rpm at a temperature of 30 ± 2 °C after 60 h incubation using Central Composite Design (CCD). Yeast cells grown under such conditions increased FAME yield from 84.0 to 92.98 % when the transesterification reaction was carried out, in comparison to those cultivated in the initial medium.
Annals of Microbiology 09/2013; 63(3):929-939. DOI:10.1007/s13213-012-0546-0 · 0.99 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Abstract The synthesis of dichloropropyl acrylates from dichloropropyl dodecanoates through a transesterification process using diverse commercial lipases and whole cells (fungal resting cells) is presented. The synthesis was carried out in a solvent-free media using a conventional batch system and a packed bed reactor (PBR). The effect of water activity on the process depended on the lipase used. The commercial enzyme CALB (Candida antarctica lipase B immobilized onto a macroporous acrylic resin) showed the best performance as a biocatalyst, achieving a yield of 50% and productivity of 7.2 ++mol min G êÆ1 g G êÆ1 in the batch reactor and 33% and 35.8 ++mol min G êÆ1 g G êÆ1 in the PBR. Finally, polymeric material was prepared by suspension polymerization of the dichloropropyl acrylates synthesized using PBR. Particles with diameters between 170 and 380 ++m were obtained with a yield of 85% after 18 h reaction
Journal of Molecular Catalysis B Enzymatic 04/2013; 92:7-13. DOI:10.1016/j.molcatb.2013.03.005 · 2.13 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: This study reports the high enantiomeric preference of whole cell lipase from Aspergillus flavus wild-type that allows the preparation of a chiral secondary alcohol. Whole cells prepared from a wild-type Aspergillus flavus strain were used as biocatalysts to prepare (R)-1-phenylethyl acetate. (R)-1-Phenylethanol was esterified into (R)-1-phenylethyl acetate with a 94.6% enantiomeric excess (ee) within 24 h at 40 °C and (S)-1-phenylethanol remained in the reaction medium with a >99%ee. Besides, this biocatalyst allows the preparation of ethyl laurate and a mixture of 2-chloro-1-(chloromethyl)ethyl acrylate and 2,3-dichloro-1-propyl acrylate. The ethyl laurate yield was 96%, whereas the synthesis of a mixture of the acrylate regioisomers, 2-chloro-1-(chloromethyl)ethyl acrylate and 2,3-dichloro-1-propyl acrylate gave similar yields to those obtained using commercial lipases.
Journal of Molecular Catalysis B Enzymatic 02/2014; 100:78–83. DOI:10.1016/j.molcatb.2013.12.005 · 2.13 Impact Factor
Data provided are for informational purposes only. Although carefully collected, accuracy cannot be guaranteed. The impact factor represents a rough estimation of the journal's impact factor and does not reflect the actual current impact factor. Publisher conditions are provided by RoMEO. Differing provisions from the publisher's actual policy or licence agreement may be applicable.