جستجوی مقالات مرتبط با کلیدواژه « enzyme immobilization » در نشریات گروه « شیمی »

In this paper, the immobilization of lipase from Candida rugosa on hydrophilic Na-montmorillonite (MT) and hydrophobic modified montmorillonite (MTS) is investigated. Hydrophobic MTS was prepared by changing the nature of hydrophilic MT with cetrimonium bromide surfactant. The enzymatic activity of lipase immobilized on Na-montmorillonite (LMT) and lipase immobilized on modified montmorillonite (LMTS) was investigated in the production of biodiesel from waste cooking oil. The support modification and enzyme immobilization were evaluated by BET, XRD, and SEM techniques. The effects of temperature, time, water content, and the molar ratio of methanol to oil on biodiesel yield were also investigated. The results showed that the activity of LMTS was much better than LMT. Under optimal conditions, the biodiesel yield produced by LMTS was about 86.4%. LMTS showed good storage stability, and after 30 days of storage at 4 ℃, the biodiesel yield was about 64.2%, while the biodiesel yield of free lipase (FL) was about 57.1%. In addition, LMTS had good reusability compared to LMT, and the biodiesel yield after 10 cycles was about 51.6%.

Enzymes or microorganisms are widely used in food preparation. With the advancement of technology, new enzymes with a wide range of applications and properties have been developed, and new fields of application are still being investigated. Microorganisms such as bacteria, yeasts, and fungi and their enzymes are widely used in many foods to improve flavor and texture and have many economic benefits for industries. Enzymes are also able to remove organic substances from food wastes effectively. Microbial enzymes are preferred sources over plants or animals due to their many advantages such as easy production, cost-effectiveness, and compatibility. However, the use of enzymes in processes has a series of disadvantages. Due to the high price of enzymes, enzymatic processes are one of the most expensive reactions. They are also sensitive to environmental conditions and can easily change their nature and lose their properties. Using a heterogeneous catalyst and immobilized enzymes on a solid support is a method that can make the recycling of enzymes possible. In this research, after examining the structure and types of enzymes, the thermodynamics of enzyme reactions and methods of enzyme stabilization were studied. Finally, recent advances in enzyme technology for food industries and a comprehensive list of enzymes used in food processing, the microbial source of these enzymes, and their wide range of applications are discussed.

Nowadays, enzyme immobilization on the nano carriers was applied in food industry. In this study, Inulinase enzyme was immobilized on the magnetite nanoparticles functionalized with protein nanoparticles through covalent attachment. Inulinase can produce high fructose syrup from inulin in a one-step enzymatic process. The Inulinase was immobilized in order to increase enzyme stability under extreme conditions of industrial processes, reusability, reduce the risk of environmental pollution with the enzyme protein, reducing the cost of the final products and the ability of using bioreactors with immobilized enzyme in continuous system. In addition, the immobilized enzyme on the magnetite nanoparticles can be separated from the reaction medium by a magnetic field and it is not necessary to use of other uneconomical methods such as centrifugal separation and filtration. Therefore, in the first step, the magnetite nanoparticles were prepared by co-precipitation method. Then, in the second step, the soy protein isolate nanoparticles were synthesized by cold gelation method and then the magnetite nanoparticle’s surface was coated for modification and stabilization. In the third step, the enzyme was immobilized on the magnetite carrier through covalent attachment via glutaraldehyde. In this study, scanning electron microscope (SEM), dynamic light scattering (DLS) and fourier transform spectroscopy (FTIR) were used for analyze the particle size, shape, morphology and functional characteristics of magnetite nanoparticles and enzyme immobilization in all steps of preparation. Based on the SEM results, the size of nanomagnetite were in the range of 20 to 50 nm with the mean diameter of about 35 nm. The nanomagnetite obtained possessed spherical morphology, uniformly distributed. The size of soy protein isolate (SPI) nanoparticles according to the initial SPI amount (gr %) were in the range of 100-600 nm by using DLS technique. FTIR method confirms proper enzyme immobilization on the functionalized nanomagnetite by protein.