A study on the enzymatic properties and reuse of cellulase immobilized with carbon nanotubes and sodium alginate

Li-Juan Li,Gui-Ping Ma,Yue-Yu Ma,Yue-Lin Chen,Wen-Jing Xia

doi:10.1186/s13568-019-0835-0

Abstract

Cellulase has many potential applications in ethanol production, extraction of medicinal ingredients, food, brewing, oil exploration, environmental protection. However, the widespread use of cellulase is limited by its relatively high production costs and low biological activity. Therefore, we studied the enzymatic properties and reusability of cellulase immobilized on multiwalled carbon nanotubes and sodium alginate for the first time. The results showed that the optimum temperature and pH of immobilized cellulase was 40 °C and 3.0, respectively. After 1 month of storage at 4 °C, the enzyme activity of immobilized cellulase dropped to 71.2% of the baseline. Immobilized cellulase was proved to be reusable and maintained ~ 70% of its activity after 7 cycles of repeated use. Versus free cellulase, the immobilized cellulase showed good thermal stability, pH resistance, storage stability and reusability, which could be beneficial in large-scale industrial manufacturing processes.

Highlights

Agricultural countries, such as China, have many straw crops, most of which are accumulated or incinerated in the soil
One alternative solution is converting the straw into gas or liquid fuel to produce energy and minimize pollution concurrently (Li et al 2009; Duarte et al 2013). It is currently limited by high production costs, low enzymatic activity and high consumption of cellulase
Immobilized enzymes were allowed the enzyme to be reused in multiple cycles to lower the production costs and overcome such technical bottlenecks (Zhang et al 2005; Wu and Ma 2008; Tao et al 2006)

Summary

Introduction

Agricultural countries, such as China, have many straw crops, most of which are accumulated or incinerated in the soil. These crop wastes are leading to pollution and a waste of resources. One alternative solution is converting the straw into gas or liquid fuel to produce energy and minimize pollution concurrently (Li et al 2009; Duarte et al 2013). It is currently limited by high production costs, low enzymatic activity and high consumption of cellulase. Carrier materials chosen to immobilize cellulase were nanoscale materials (Bohara et al 2016), natural polymers (Andriani et al 2015), mesoporous materials (Zhang et al 2016a, b) and magnetic materials (Han et al 2018); high

Methods

Results

Conclusion