EFFECIENCY OF IMMOBILIZED POLYPHENOL OXIDASE ON SOME TEXTILE DYES DEGRADATION USING BATCH OPERATION SYSTEM BY PACKED BED BIOREACTOR

S I Hussein

doi:10.36103/ijas.v50i3.711

Abstract

In the current study, three types of common plants, namely Tomato (Solanum lycopersicum), Cucumber (Cucumis sativus) and Orange (Citrus sinensis) were obtained and screened for their polyphenol oxidase (PPO) activity, Among the three plants, Solanum lycopersicum was chosen with maximum enzymatic activity, it had the highest productivity of the enzyme (23733 U/mg protein).The PPO from Solanum lycopersicum was purified using two steps: concentration by sucrose and gel filtration by using Sephacryl S-200. The results showed an increase in the final purification folds by 2.4 times with an enzyme yield of 32.6%. The immobilization studies showed that PPO was more stable when immobilized on chitosan by covalent linkage with immobilization ratio of 62%, in comparison with agar-agar by entrapment method (36%). The removal efficiency of crude and partial purified PPO was studied with textile dyes, including yellow, red, black and blue dyes at optimum conditions: pH 5, temperature 40oC after 3 hrs. Maximum removal efficiency of dyes observed with crude PPO were 53.9, 81.4, 86.5 and 79.6% respectively. However, purified PPO displayed removal efficiency reached 60.3, 84.3, 84.6 and 77.5% respectively. The potential of immobilized PPO on chitosan was evaluated by decolorization of black textile dye in packed bed bioreactor in batch operation. The results indicated that immobilized PPO in batch operation has the ability to remove 99% of the dye after 2 hrs, and the results showed a positive relationship between the degradation rate and incubation time in batch operation.

Highlights

In line with the evolution of the petroleum industry, the area of oil-polluted soil has increased continuously
Purification of polyphenol oxidase (PPO) Polyphenol oxidase enzyme was extracted from Solanum lycopersicum by homogenization in the blender at room temperature
The crude PPO was purified from the unwanted proteins and other components through concentration by sucrose, and gel filtration using Sephacryl –S200, as follows: Enzyme concentration by sucrose The crude extract produced was initially subjected to concentration by sucrose

Summary

INTRODUCTION

In line with the evolution of the petroleum industry, the area of oil-polluted soil has increased continuously. PPO activity Polyphenol oxidase enzyme activity was estimated according to the method described by Zian and Pekyardimici [33] using orthocatechol as a substrate. Purification of PPO Purification of the enzyme was determined by two methods: concentration by dialysis and gel filtration. Immobilization of PPO enzyme Immobilization of PPO by entrapment methods Entrapment in agar-agar 2ml of purified PPO was mixed with 5ml of sterile agar-agar solution (2%) at 40oC. The gluteraldehyde bounded chitosan was washed extensively with water to remove the unbounded gluteraldehyde, mixed with 10ml of purified enzyme solution at 4oC overnight for enzyme immobilization [5]. The resulting chitosan-gluteraldehyde-PPO conjugates were separated and washed, immobilized enzyme activity was determined. To determine the decolorization rate of the dye by chitosan immobilized PPO, the samples from the outlet of the reactor were taken at different incubation times (0, 1, 2, 3 and 24hrs). The percentage of removal efficiency for the dye was calculated by the difference in absorbance at λ max according to Zhang et al [32]

RESULTS AND DISCUSSION

Production of xylanase from an alkali tolerant

Phenolic azo dye oxidation by laccase from