Production of Trans-Cinnamic Acid by Immobilization of the Bambusa oldhamii BoPAL1 and BoPAL2 Phenylalanine Ammonia-Lyases on Electrospun Nanofibers

Abstract

Phenylalanine ammonia-lyase (PAL) catalyzes the nonoxidative deamination of phenylalanine to yield trans-cinnamic acid and ammonia. Recombinant Bambusa oldhamii BoPAL1/2 proteins were immobilized onto electrospun nanofibers by dextran polyaldehyde as a cross-linking agent. A central composite design (CCD)-response surface methodology (RSM) was utilized to optimize the electrospinning parameters. Escherichia coli expressed eBoPAL2 exhibited the highest catalytic efficiency among four enzymes. The optimum conditions for fabricating nanofibers were determined as follows: flow rate of 0.10 mL/h, voltage of 13.8 kV, and distance of 13 cm. The response surface models were used to obtain the smaller the fiber diameters as well as the highest PAL activity in the enzyme immobilization. Compared with free BoPALs, immobilized BoPALs can be reused for at least 6 consecutive cycles. The remained activity of the immobilized BoPAL proteins after storage at 4 °C for 30 days were between 75 and 83%. In addition, the tolerance against denaturants of the immobilized BoPAL proteins were significantly enhanced. As a result, the dextran polyaldehyde natural cross-linking agent can effectively replace traditional chemical cross-linking agents for the immobilization of the BoPAL enzymes. The PAL/nylon 6/polyvinyl alcohol (PVA)/chitosan (CS) nanofibers made are extremely stable and are practical for industrial applications in the future.

Phenylalanine, Tyrosine, and DOPA Are bona fide Substrates for Bambusa oldhamii BoPAL4

“…Recently, several studies have successfully immobilized PAL proteins on different carriers [44][45][46][47]. Electrospun nanofibers combined with dextran polyaldehyde crosslinker are suitable for BoPAL1 and BoPAL2 immobilization [47]. In this study, we showed that BoPAL4 had broad substrate specificities for synthesizing at least three products.…”

“…Trans-cinnamic acid derivatives are shown to have useful effects in human health, such as anti-obesity and anti-microbial activities [9,10]. Recently, several studies have successfully immobilized PAL proteins on different carriers [44][45][46][47]. Electrospun nanofibers combined with dextran polyaldehyde crosslinker are suitable for BoPAL1 and BoPAL2 immobilization [47].…”

Cloning of Three Cytokinin Oxidase/Dehydrogenase Genes in Bambusa oldhamii

“…Bambusa oldhamii , green bamboo, is a perennial plant in the tropics and subtropics, and bamboo shoot is an economic vegetable in far-eastern Asia [ 38 , 39 , 40 , 41 , 42 , 43 , 44 ]. Bamboo is one of the fast-growth timber plants, which are controlled by plant hormones, especially cytokinins [ 45 ].…”

Immobilization of BoPAL3 Phenylalanine Ammonia-Lyase on Electrospun Nanofibrous Membranes of Polyvinyl Alcohol/Nylon 6/Chitosan Crosslinked with Dextran Polyaldehyde

“…Functional nanomaterials, such as nanofibers, nanoparticles, and nanocomposites, have drawn interest and attention because of their distinctive characteristics and intriguing uses in enzyme immobilization techniques [ 35 , 36 , 37 ]. Owing to their high surface-to-volume ratio, nanofibrous membranes can offer a sizable area for protein immobilization [ 36 , 38 ]. The electrospinning technique is a convincing method that has emerged in recent years that uses an electrostatic force to transform polymer solutions into nanofibrous membranes [ 38 , 39 , 40 ].…”

“…Owing to their high surface-to-volume ratio, nanofibrous membranes can offer a sizable area for protein immobilization [ 36 , 38 ]. The electrospinning technique is a convincing method that has emerged in recent years that uses an electrostatic force to transform polymer solutions into nanofibrous membranes [ 38 , 39 , 40 ]. Previous studies have shown that immobilized enzymes have increased the resistance to extreme pH and temperature [ 41 ], increased reusability [ 42 ], extended storage stability, enhanced enzymatic activities [ 38 , 43 ], and so on.…”