An enzyme-displaying yeast as a whole-cell biocatalyst is an alternative to immobilized enzyme, due to its low-cost preparation and simple recycle course. Here, lipase-displaying Pichia pastoris whole-cell was used as a biocatalyst to synthesize diisooctyl adipate in the non-aqueous system. The maximum productivity of diisooctyl adipate was obtained as 85.0% in a 10 mL reaction system. The yield could be reached as high as 97.8% when the reaction system was scaled up to 200 mL. The purity obtained is 98.2% after vacuum distillation. Thus, the lipase-displaying P. pastoris whole-cell biocatalyst was promising in commercial application for diisooctyl adipate synthesis in non-aqueous phase.
Adipates ; metabolism ; Industrial Microbiology ; Lipase ; metabolism ; Pichia ; metabolism

A rapid gas chromatography method was developed for determination of lipase activity using tributyrin as substrate. The standard curves of butyric acid hydrolyzed from tributyrin were linear in the range of 0.11-11.35 mmol L(-1). The recoveries of low, moderate and high concentrations of tributyrin were 90.3%, 104.6%, 89.4% with RSD of 3.01%, 4.50%, 6.64%, respectively. The incubation time was only 5 minutes which was less than with the half time of the conventional titrimetry and spectrophotometry. The optimum pH value was 7.5 and the optimum temperature was 32 degrees C. Based on the Lineweaver-Burk plots, the Michaelis-Menten constant was 0.25 mmol mL(-1). The effect of orlistat on the enzyme inhibiting activity was studied to prove the accuracy of this method. It was found that the half-inhibition concentration (IC50) of orlistat was 0.0485 mg mL(-1). The small total reaction volume, the simple treating procedures, the high accuracy and precision present the advantages of the new method.
Chromatography, Gas ; methods ; Lipase ; analysis ; metabolism ; Triglycerides ; metabolism

Biodiesel, an alternative diesel fuel, fatty acid alkyl ester, is made from renewable biological sources such as vegetable oils and animal fats. Two processes for biodiesel synthesis, enzymatic lipase catalytic esterification from fatty acid and transesterification from oils and fats, was investigated. The effects of various lipases, enzyme amount and purity, solvent, water absorbent, inhibition of short chains alcohol, specificity of substrate, molar ratio of substrate on esterification were studied in detail. The esterification degree with the optimal parameter and process can reach up to 92%. The purity of biodiesel obtained by separation and purification is up to 98%, and the half-life of the immobilized lipase for the esterification process can be up to 360hr, Moreover, the preliminary studies of the transesterification including the amount of methanol and mode of adding methanol into reaction system were made. The transesterification degree with adding methanol stepwise can reach 83%.
Biofuels ; Enzymes, Immobilized ; metabolism ; Esterification ; Lipase ; metabolism ; Methanol ; metabolism ; Plant Oils ; metabolism

We investigated the transesterification of crude cottonseed oil with methyl acetate to biodiesel, by using Lipozyme TL IM and Novozym 435 as catalysts. Results showed that the biodiesel yield significantly increased with the addition of methanol into the reaction system, and the highest biodiesel yield of 91.83% was achieved with the optimum conditions as follows: n-hexane as solvent, molar ratio of methyl acetate to oil 9:1, 3% methanol based on the oil mass to inhibit the creation of acetic acid, 10% Lipozyme TL IM and 5% Novozym 435 as catalyst based on the oil mass, reaction temperature 55 degrees C and reaction time 8 h. Additionally, we explored the kinetics of lipase-catalyzed crude cottonseed oil to biodiesel, and proposed a kinetic model.
Acetates ; metabolism ; Biofuels ; analysis ; Catalysis ; Cottonseed Oil ; chemistry ; metabolism ; Enzymes, Immobilized ; metabolism ; Lipase ; metabolism

Lipase-mediated biodiesel production becomes increasingly important because of mild reaction conditions, pollution free during the process and easy product separation. Compared with traditional immobilized lipase, whole cell biocatalyst is promising for biodiesel production because it is easy to prepare and has higher enzyme activity recovery. Rhizopus oryzae IFO4697 can be used as the catalyst for biodiesel production. To further study the stability of the whole cell biocatalyst is extremely important for its further application on large scale. This paper focuses on the stability study of Rhizopus oryzae IFO4697 when used for the methanolysis of renewable oils for biodiesel production. The results showed that water content was important for achieving high catalytic activity and good stability of the biocatalyst. The optimum water content was found to be 5%-15%. Both particle size and desiccation methods showed no obvious effect on the stability of the biocatalyst. With GA cross-linking pretreatment, the stability of the biocatalyst could be improved significantly. When Rhizopus oryzae IFO4697 repeatedly used for next batch reaction, direct vacuum filtration was found to be a good way for the maintenance of good stability of the biocatalyst. Under the optimum reaction conditions, the methyl ester yield could keep over 80% during 20 repeated reaction batches.
Biocatalysis ; Bioelectric Energy Sources ; microbiology ; Biofuels ; Cells, Immobilized ; metabolism ; Lipase ; metabolism ; Rhizopus ; metabolism ; Soybean Oil ; metabolism

Enzymatic esterification by reacting caparic acid with glycerol in solvent-free system was studied. Lipases from Pseudomonas fluoresces(PFL), Mucor miehei(MML) and Candida antarictica(CAL) possessed good catalytic activity. The optimal reaction conditions to convert capric acid with CAL are: 60 degrees C, 20-100 u of CAL per gram capric acid, 12% (W/W) of initial water content in glycerol. CAL does not express its 1,3-specificity in final product. Mechanical fraying denatured CAL partly. 96.4% of catalytic activity of CAL recovered after 5 batches of reaction. Extraction with sodium carbonate solution can decrease acid value of product from 9.8 mg KOH/g to 0.68 mg KOH/g. Applying the enzymatic esterification in open system, under vacuum or dehydrating with molecular sieves all dehydrate effectively. Molar ratio of reactants does not influence the total conversion of capric acid but influences the yield of monoglyceride. With certain protocols, the reaction period could be shortened dramatically; conversion of capric acid reached 96.9% in 5 h.
Catalysis ; Decanoic Acids ; isolation & purification ; metabolism ; Glycerol ; isolation & purification ; metabolism ; Lipase ; metabolism

Studies on the variation of amylase, lipase and lrotease activity of Whitmania pigra in 0-6 months old using 3, 5-dinitro- salicylic acid colorimetry, right-nitrophenyl palmitate ester (ρ-NPP) colorimetry and folin-phenol method. The results showed that pro- tease activity remained low before 1.5 months old and with the highest activity in 2 months old, but after showing a small peak in 4 months, alkaline protease rapid declined. Amylase was low at born, then gradually increased the activity of the highest in 2.5 months old. Lipase with a strong vitality at birth, then 1 month with minimum and 2 months peaked, but appeared a small peak in 4 months old. In summary, only lipase exhibits strong activity at birth, lipase with the strongest activity in the digestive tract during develop- ment. Protease, lipase and amylase with the strongest activity at 2-3 months old, but were decreased after 4 months old.
Age Factors ; Amylases ; metabolism ; Animals ; Leeches ; enzymology ; Lipase ; metabolism ; Peptide Hydrolases ; metabolism

Biological synthesis of L-Ascorbyl Palmitate in organic system were studied in this text. The contradiction between conversion of vitamin C and concentration of L-Ascorbyl Palmitate were resolved. High conversion of vitamin C and concentration of L-Ascorbyl Palmitate were obtained by Novo435. A series of solvents(log P from -0.24 to 3.5 )were investigated for the reaction,and acetone was found to be the most suitable from the standpoint of the enzyme activity and solubility of L-ascorbic. And the equilibrium of the reaction was affected by the addition of the molecular sieves and temperature. Reaction carried out at 60 degrees C and with 20% 0.4nm molecular sieves is good for the enzyme to keep its activity and for making the equilibrium go to the product. With 1.094 g palmitic acid, 0.107 g vitamin C and 0.020 g Novo435, rotate rate of 200 r/min, the conversion of ascorbic reached 80% and the concentration of L-ascorbyl palmitate is 20 g/L after 48 h. Furthermore, reaction batch of Novo435 and substrates recycle were observed, the result indicated that Novo435 may used 4-5 times continuously with high conversion. And 6-O-unsaturated acyl L-ascorbates were synthesized through Novo435 condensation of ascorbic acid and various unsaturated fatty acids with high conversion in this text.
Ascorbic Acid ; analogs & derivatives ; biosynthesis ; Catalysis ; Enzymes, Immobilized ; chemistry ; metabolism ; Lipase ; chemistry ; metabolism

The specific expression of TGH and HSL genes in different tissues of Bamei pig was investigated by RT-PCR and Western blot in this study. The result of RT-PCR showed that the expression of HSL could be detected in all these seven tissues examined, and which was higher expressed in fat, lower in heart, liver, lung, spleen and kidney. Expression of TGH gene could also be detected in seven tissues, and higher in liver and fat, lower in heart and kidney and lowest in spleen and lung. The result of Western blot showed that, HSL gene was highest expressed in epiploica fat and subcutaneous fat, higher in other tissues, but couldn' t be detected in kidney. Expression of TGH was detected in epiploica fat, subcutaneous fat, liver, lung and spleen, and highest in fat and liver, but it hadn't be found in heart and kidney. These results suggested that both HSL and TGH could be regulated by post-transcriptional, and their function was involved in different tissues.
Animals ; Gene Expression Regulation ; Lipase ; genetics ; metabolism ; Male ; Sterol Esterase ; genetics ; metabolism ; Swine ; Tissue Distribution

The synthesis of vitamin A plamitate in organic solvent with vitamin A acetate and ethyl palmitate with immobilized lipase from Candida sp. was studied. The influences of solvent, the molar ratio of substrates, the reaction temperature and time, and the water concentration were optimized and the best result was obtained by transesterification from 0.100 g vitamin A acetate and 0.433 g ethyl palmitic, at 30 degrees C, in 10 mL petroleum ether, containing 0.2% of water (V/V), with 1.1 g lipase. In these conditions, the yield of vitamin A palmitate reached 83% in 12 h. The immobilized lipase was reused about 5 batches.
Candida ; enzymology ; Catalysis ; Enzymes, Immobilized ; metabolism ; Lipase ; metabolism ; Vitamin A ; analogs & derivatives ; chemical synthesis