scholarly journals The influence of composition of poly(n-isopropylacrylamide-co-itaconic acid) hydrogel on immobilized Candida rugosa lipase activity

2008 ◽  
Vol 62 (6) ◽  
pp. 339-344
Author(s):  
Nikola Milasinovic ◽  
Melina Kalagasidis-Krusic ◽  
Zorica Knezevic-Jugovic ◽  
Jovanka Filipovic
Keyword(s):  
Mechanical Properties ◽  
Itaconic Acid ◽  
Lipase Activity ◽  
Acid Content ◽  
Immobilized Enzyme ◽  
In Situ Polymerization ◽  
Immobilized Lipase ◽  
Candida Rugosa ◽  
Candida Rugosa Lipase

The application of lipases as catalysts in chemical reactions has been deterred by the high cost of isolation and purification of enzymes, the instability of their structure when they are isolated from their natural environment, contamination of products with residual protein, their sensitivity to process conditions, etc. These problems could be overcome using immobilized lipases. Immobilization is achieved by fixing enzymes to or within solid supports and as a result a heterogeneous system is obtained. The present paper reports on the immobilization of Candida rugosa lipase in hydrogels based on N-isopropylacrylamide and itaconic acid. Immobilization of lipase is carried out by two different methods. In the first method, lipase is added to the reaction mixture before polymerization and crosslinking (in situ polymerization), while in the second method the synthetized hydrogels are immersed in lipase solution and left to rich the equilibrium swelling. The specific activities of the immobilized lipase were determined in both cases and compared. The amount of the immobilized lipase is higher if the immobilization is carried out by immersing hydrogel in lipase solution. It was observed that in both cases lipase activity increases with an increase of the itaconic acid content up to 10 wt% and thereafter decreases. From the measurements of shear storage moduli (G') it was concluded that the increase of the itaconic acid content decreases the mechanical properties of the hydrogels. SEM analysis confirmed the highly porous structure of hydrogels. It was found that greater pores were achieved when the enzyme was immobilized by in situ polymerization. When the enzyme was immobilized by in situ polymerization the itaconic acid content had not great effect on the mass of the immobilized enzyme, except for the 100/0 sample. On the contrary, for the samples where the enzyme was immobilized by swelling, the increase of the itaconic acid content increases the mass of the immobilized enzyme. Concerning the activity of the immobilized lipase, the swelling degree and mechanical properties of the investigated hydrogels, the best results were performed by the 95/5 hydrogel sample.

Synthesis and Characterizations of Poly(Butylene Succinate) Copolyester

2014 ◽  
Vol 1015 ◽  
pp. 381-384
Author(s):  
Li Liu ◽  
Li Hai Cai ◽  
Dan Liu ◽  
Jun Xu ◽  
Bao Hua Guo
Keyword(s):  
Mechanical Properties ◽  
Polymer Matrix ◽  
Crystallization Temperature ◽  
In Situ Polymerization ◽  
Nucleating Agent ◽  
Single Fiber ◽  
Butylene Succinate ◽  
Crystallization Behaviors ◽  
Polymerization Method

The poly (butylene succinate) (PBS) and 3 wt% attapulgite (ATP) reinforced PBS/ATP nanocomposites with 1,6-hexanediol were fabricated using an in situ polymerization method. The crystallization behaviors indicated that ATP had effectively acted as nucleating agent, resulting in the enhancement on the crystallization temperature. The SEM results showed a superior interfacial linkage between ATP and PBS. Also, ATP could disperse as a single fiber and embed in the polymer matrix, which resulted in the improved mechanical properties.

Mechanical Properties of Thermoplastic Composites via In Situ Polymerization from Cyclic Oligomers

2013 ◽  
Vol 750-752 ◽  
pp. 7-10
Author(s):  
Kou An Hao ◽  
Zhen Qing Wang ◽  
Li Min Zhou
Keyword(s):  
Mechanical Properties ◽  
In Situ Polymerization ◽  
High Viscosity ◽  
Thermoplastic Composites ◽  
Thermoplastic Matrix ◽  
Polymerization Catalyst ◽  
Short Beam ◽  
Beam Shear ◽  
Cyclic Oligomers

Fiber impregnation has been the main obstacle for thermoplastic matrix with high viscosity. This problem could be surmounted by adapting low viscous polymeric precursors Woven basalt fabric reinforced poly (butylenes terephthalate) composites were produced via in-situ polymerization at T=210°C. Before polymerization, catalyst was introduced to the reinforcement surface with different concentration. DSC is used to determine the polymerization and crystallization. SEM is used to detect whether the catalyst existed on surface. Both flexural and short-beam shear test are employed to study the corresponding mechanical properties.

scholarly journals Improved Catalytic Performance of Carrier-Free Immobilized Lipase by Advanced Cross-Linked Enzyme Aggregates Technology

2021 ◽  
Author(s):  
Xia Jiaojiao ◽  
Yan Yan ◽  
Bin Zou ◽  
Adesanya Idowu Onyinye
Keyword(s):  
Low Cost ◽  
Immobilized Lipase ◽  
Candida Rugosa ◽  
Residual Activity ◽  
Candida Rugosa Lipase ◽  
Catalytic Performance ◽  
Functional Surface ◽  
Carrier Free ◽  
Effective Synthesis ◽  
Repeated Use

Abstract The cross-linked enzyme aggregates (CLEAs) are one of the technologies that quickly immobilize the enzyme without a carrier. This carrier-free immobilization method has the advantages of simple operation, high reusability and low cost. In this study, ionic liquid with amino group (1-aminopropyl-3-methylimidazole bromide，IL) was used as the novel functional surface molecule to modify industrialized lipase (Candida rugosa lipase, CRL). The enzymatic properties of the prepared CRL-FIL-CLEAs were investigated. The activity of CRL-FIL-CLEAs (5.51 U/mg protein) was 1.9 times higher than that of CRL-CLEAs without surface modification (2.86 U/mg protein). After incubation at 60℃ for 50 min, CRL-FIL-CLEAs still maintained 61% of its initial activity, while the value for CRL-CLEAs was only 22%. After repeated use for five times, compared with the 22% residual activity of CRL-CLEAs, the value of CRL-FIL-CLEAs was 51%. Further kinetic analysis indicated that the Km values for CRL-FIL-CLEAs and CRL-CLEAs were 4.80 mM and 8.06 mM, respectively, which was inferred that the affinity to substrate was increased after modification. Based on the above results, it was indicated that this method provided a new idea for the effective synthesis of immobilized enzyme.

scholarly journals The Effect of the Parameters of T-RTM on the Properties of Polyamide 6 Prepared by in Situ Polymerization

Materials ◽  
2019 ◽  
Vol 13 (1) ◽  
pp. 4 ◽  
Author(s):  
Orsolya Viktória Semperger ◽  
András Suplicz
Keyword(s):  
Mechanical Properties ◽  
Automotive Industry ◽  
Cycle Time ◽  
In Situ Polymerization ◽  
Rapid Development ◽  
Polyamide 6 ◽  
Raw Material ◽  
Short Cycle ◽  
Short Cycle Time

With the rapid development of the automotive industry, there is also a significant need to improve the raw materials used. Therefore, the demand is increasing for polymer composites with a focus on mass reduction and recyclability. Thermoplastic polymers are preferred because of their recyclability. As the automotive industry requires mass production, they require a thermoplastic raw material that can impregnate the reinforcement in a short cycle time. The most suitable monomer for this purpose is caprolactam. It can be most efficiently processed with T-RTM (thermoplastic resin transfer molding) technology, during which polyamide 6 is produced from the low-viscosity monomer by anionic ring-opening (in situ) polymerization in a tempered mold with a sufficiently short cycle time. Manufacturing parameters, such as polymerization time and mold temperature, highly influence the morphological and mechanical properties of the product. In this paper, the properties of polyamide 6 produced by T-RTM are analyzed as a function of the production parameters. We determine the crystallinity and the residual monomer content of the samples and their effect on mechanical properties.

scholarly journals Biosynthesis of ethyl butyrate with immobilized Candida rugosa lipase onto modified Eupergit®C

Biocatalysis ◽  
2014 ◽  
Vol 1 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Daniele Spinelli ◽  
Simone Coppi ◽  
Riccardo Basosi ◽  
Rebecca Pogni
Keyword(s):  
Immobilized Lipase ◽  
Candida Rugosa ◽  
Product Yield ◽  
Candida Rugosa Lipase ◽  
Maximum Activity ◽  
Ethyl Butyrate ◽  
Molar Ratio ◽  
Practical Applications ◽  
Solvent Free Conditions ◽  
Immobilized Candida Rugosa Lipase

AbstractLipase from Candida rugosa was immobilized onto the modified Eupergit®C. The support was treated with ethylenediamine and subsequently activated with glutaraldehyde. Enzyme immobilization efficiency was 85%. The optimum pH was close to 6.5 for both the free and immobilized lipase. Immobilized lipase retained its maximum activity in a temperature range of 55 – 60°C. Subsequently, ethyl butyrate synthesis was investigated using immobilized enzyme by esterification of butyric acid with ethanol in solvent-free conditions (23% product yield) and using hexane as a solvent (65% product yield). The acid-alcohol molar ratio and different enzyme amounts were tested as efficient reaction parameters. The biocatalyst maintained 60% of its activity when reused in 8 successive batch reactions in organic solvent. Therefore, the immobilized lipase has demonstrated its potential in practical applications such as short-chain ester synthesis for the food industry.

scholarly journals Fabrication, Crystalline Behavior, Mechanical Property and In-Vivo Degradation of Poly(l–lactide) (PLLA)–Magnesium Oxide Whiskers (MgO) Nano Composites Prepared by In-Situ Polymerization

Polymers ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1123 ◽  
Author(s):  
Hui Liang ◽  
Yun Zhao ◽  
Jinjun Yang ◽  
Xiao Li ◽  
Xiaoxian Yang ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Magnesium Oxide ◽  
Bone Repair ◽  
In Situ Polymerization ◽  
Resonance Spectroscopy ◽  
Scanning Calorimetry ◽  
Biomedical Material ◽  
In Vivo Degradation

The present work focuses on the preparation of poly(l–lactide)–magnesium oxide whiskers (PLLA–MgO) composites by the in-situ polymerization method for bone repair and implant. PLLA–MgO composites were evaluated using Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and solid-state 13C and 1H nuclear magnetic resonance spectroscopy (NMR). It was found that the whiskers were uniformly dispersed in the PLLA matrix through the interfacial interaction bonding between PLLA and MgO; thereby, the MgO whisker was found to be well-distributed in the PLLA matrix, and biocomposites with excellent interface bonding were produced. Notably, the MgO whisker has an effect on the crystallization behavior and mechanical properties; moreover, the in vivo degradation of PLLA–MgO composites could also be adjusted by MgO. These results show that the whisker content of 0.5 wt % and 1.0 wt % exhibited a prominent nucleation effect for the PLLA matrix, and specifically 1.0 wt % MgO was found to benefit the enhanced mechanical properties greatly. In addition, the improvement of the degrading process of the composite illustrated that the MgO whisker can effectively regulate the degradation of the PLLA matrix as well as raise its bioactivity. Hence, these results demonstrated the promising application of PLLA–MgO composite to serve as a biomedical material for bone-related repair.

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