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Enzyme immobilization is a routine biotechnology of many industries such as pharmaceutical, chemical and food. Among the different techniques of enzyme immobilization, cross-linking methods are often used. Geniposide is a natural product extracted from gardenia and its hydrolysate genipin is one of green cross-linking agent for enzyme immobilization, but the environmental pollution and cost of the genipin extraction process have become the main obstacle to its wide application. Enzyme β-glucosidase was immobilized on chitosan by self-catalysis and further used to hydrolyze geniposide. The laccase was immobilized on Nano-SiO2 through the hydrolysate of geniposide directly acts as cross-linking agent. The simplification of the extraction steps overcomes the obstacles to the widespread use of genipin. Compared with the free laccase, the Nano-SiO2@laccase exhibited better pH stability and thermal stability. The Nano-SiO2@laccase was used to degrade Bisphenol A (BPA) and the biodegradation efficiency of the Nano-SiO2@laccase was 84.3 % after 10 cycles of reusing.

The immobilization of enzyme is an important biotechnology in industry. Enzyme immobilization by nanomaterials has attracted interest of researchers due to potentially promising application. Many enzymes had been successfully immobilized by different nanomaterials. In this work, β-glucosidase was immobilized by SiO2 nanoparticles (nano-SiO2) and zeolitic imidazolate framework-8 (ZIF-8), then the enzymatic properties of them were also compared. The nano-SiO2@β-glucosidase and the β-glucosidase@ZIF-8 achieved immobilization yield of 58.5% and 23.0%, respectively. Optimal temperature of the free β-glucosidase, nano-SiO2@β-glucosidase and the β-glucosidase@ZIF-8 were around 50 °C. Both free β-glucosidase and nano-SiO2@β-glucosidase showed maximal catalytic activity at pH 6.0, while the optimal pH of the β-glucosidase@ZIF-8 was 5.4 roughly. The nano-SiO2@β-glucosidase exhibited similar pH stability and thermal stability to those of the free β-glucosidase, and the β-glucosidase@ZIF-8 improved pH stability greatly. Moreover, after the treatment of trypsin for 4 h at 37 °C, the residual activities of the β-glucosidase@ZIF-8 was the highest that retained 94%, which provided huge potential for the application of the β-glucosidase@ZIF-8 in industry. Furthermore, the nano-SiO2@β-glucosidase and the β-glucosidase@ZIF-8 can be reused for 5 cycles with 87.5% and 88.7% residual activity, respectively.

Nanoparticles have been successfully used for immobilization of different enzymes. The enzyme immobilized by nanomaterials has promising application in the biotechnological industry. The β-glucosidase is very important in industrial field. The immobilization of β-glucosidase by nanomaterials increases its activity and reusability. In this work, the β-glucosidase was extracted from fruiting bodies of Agrocybe aegirit and was purified by anion exchange. The β-glucosidase was immobilized by SiO2 nanoparticles (nano-SiO2) crosslink with glutaraldehyde (GA). On the other hand, the β-glucosidase firstly immobilized by process adsorption and then crosslink with genipin (GP) which was produced by the hydrolysis of geniposide by β-glucosidase. Then we compared the properties of both immobilized GA-crosslinked β-glucosidase and GP-crosslinked β-glucosidase, their immobilization yields were 83.34% and 96.29% respectively. The GA-crosslinked β-glucosidase and free β-glucosidase revealed optimal pH at 6.0. The optimal pH of GP-crosslinked β-glucosidase was ranging between 4.5 and 7.5. The GA-crosslinked β-glucosidase and GP-crosslinked β-glucosidase revealed the optimal temperature at 50 °C, 70 °C respectively. For the free β-glucosidase, the optimal temperature was 55 °C. Furthermore, the GA-crosslinked β-glucosidase and GP-crosslinked β-glucosidase were characterized by scanning electron microscope (SEM). The geniposide consumption in the reaction system of GA-crosslinked β-glucosidase was analyzed by high performance liquid chromatography (HPLC).

Information concerning food composition, including information on its glucose content, is essential for modern food industry due to greater consumer awareness and expectations. In this work, the gene encoding d -glucose dehydrogenase (GDH) from Bacillus Natto was expressed in Escherichia coli BL21(DE3) firstly. Ni-IDA column was used for the purification of GDH. Then, the purified GDH was used to construct a color system with stable and effective measurement of concentration of d -glucose. The smart phone photographing and the software Microsoft Photoshop have been used in the system for determination of the color. The enzymatic analysis system can detect the concentration of d -glucose from 5 mM to 40 mM, and other various sugars has no interference to the system. The system was used to quantitatively detect the concentration of d -glucose in honey. The system can be used for convenient and rapid detection of d -glucose in food, especially for large numbers of samples.

Metal-organic framework (MOF) has generated a lot of research interests for it can be employed as immobilization material for enzyme. There are many small molecules in enzyme solution during the extraction process, such as NaCl. It is important to study the effects of the small molecules on MOFs. Here we report a facile and efficient method to encapsulate (R)-1-phenylethanol dehydrogenase ((R)-PEDH) into zeolitic imidazolate framework-8 (ZIF-8). In this work, the effects of NaCl on shape of ZIF-8 and enzyme encapsulation have been investigated. The scanning electron microscope (SEM) results showed that 0.1 M NaCl affect the morphology of ZIF-8 while the crystal structure was not changed analyzed by X-ray diffraction (XRD), and 0.1 M NaCl consisted in the encapsulation system of (R)-PEDH@ZIF-8 enhanced the activity up to 2.5 folds than no NaCl consisted during prepared (R)-PEDH@ZIF-8. The (R)-PEDH@ZIF-8 (prepared with 0.1 M NaCl) enhanced the storage stability and resist ability against trypsin, and the (R)-PEDH@ZIF-8 has been successfully reused.

In this study, a system of photocatalysis for NAD+ regeneration of enzymatic catalysis was constructed. The optimal conditions for the coupling reaction of photocatalysis and biocatalysis were explored. Blue light was chosen for the efficient reaction and the optimal concentration of VB2 (vitamin B2, riboflavin) was determined. NAD+-dependent (R)-1-phenylethanol dehydrogenase was used in the reaction for transforming (R)-1-phenylethanol to acetophenone. The byproducts of the reaction were just H2O and O2 by means of catalase. The coupling reaction of catalysis and photocatalysis can be used for obtaining (S)-1-phenylethanol through racemization of 1-phenylethanol. Copyright © 2019 BCREC Group. All rights reserved

For multi-sensor target recognition system in a complex interference environment, the uncertainty of fused information, produced by multifold factors, leads to the fallibility of system output. This paper presents a multi-sensor target recognition model in order to solve the problem. The model revises the bias between the prior distribution and the factual distribution of target properties with the use of class confidence distance measure, and improves reliability of the target class estimate. Before fusion, the sensor information is filtrated by consistency measure and sensor confidence, which dispose conflicting information and false information effectively. The simulation results show that the model ensures accurate output of system when environment changes dynamically and the reliability of the sensors is depressed.

Efficient diagnosis of faults in digital circuits requires high quality diagnostic test sets that are generated by effective algorithm. In this work, novel optimization algorithms for diagnostic test generation are proposed that require significantly less time than previous methods. The diagnostic test generation is performed using particle swarm optimization (PSO) or improved PSO, and fault simulator. Experimental results illustrate the effectiveness of the approach. STPG based on improved PSO is generally superior to both GA-based STPG and PSO-based STPG in terms of achieved fault coverage and required CPU time.

According to the insufficiencies existing in Dempster-Shafer theory of evidence when it deals with the conflicting evidences, many scholars have presented modified rules based on reallocation of the basic probability assigned to conflict. A new combination rule is presented to mend the disadvantages of the rules. This rule analyzes the validity of evidence set according as the extent of conflict with the use of the reliability of evidential sources and support measure of the evidence, and realizes information fusion rationally. Experiments shows that the new combination rule overcomes the limitations, and the outputs are constringent on the aspect of rationality, which enhances robustness of systems effectively.

For the multi-sensor multi-target data association problem, a novel particle swarm optimization (PSO) algorithm based S-dimensional (S-D) assignment method is proposed in this paper. By a combinational optimal way, it could find the minimum objective cost to be the best solution. Furthermore, the best solution could be searched soon through reducing the search region. The reason is that the validity of the candidate measurements is considered in particle swarm initialization, cross-over rules, and mutation rules. The PSO using different rules and GA are simulated for data association in the presence of fault alarms, and missed detections. The comparison testifies the proposed approach is effective.

According to the insufficiencies existing in the rule of D-S evidence theory, Yager's rule and its modified rules when evidences conflict, this paper presented a new combination rule based on reallocation of the basic probability assigned to conflict. This rule considered the actual background that systems are applied to, and analyzed the validity of evidences according as the extent of conflict by the reliability of evidential sources and support measure of the evidence. Experiments showed that the new combination rule overcomes the insufficiencies and enhances robustness of systems effectively, and the results are constringent on the aspect of rationality.