Immobilization of recombinant Escherichia coli on multi-walled carbon nanotubes for xylitol production

• Published in: Enzyme and microbial technology 2020-04, Vol.135, p.109495-109495, Article 109495
• Main Authors: Abd Rahman, Noor Hidayah, Md. Jahim, Jamaliah, Abdul Munaim, Mimi Sakinah, A. Rahman, Roshanida, Fuzi, Siti Fatimah Zaharah, Md. Illias, Rosli
• Format: Article
• Language: English
• Subjects: Cell immobilization; Escherichia colimulti-walled carbon nanotubes; Shake flask fermentation; Xylitol
• ISSN: 0141-0229; 1879-0909
• DOI: 10.1016/j.enzmictec.2019.109495

•The best support for cell immobilization is untreated MWCNT.•The best cultural conditions using One Factor at One Time (OFAT) approach were SOB medium, 30 °C, pH 7, 0.005 mM IPTG•The immobilized cells reduced cell lysis by up to 73 % and improved plasmid stability up to 17 % compared to the free cells.•Optimization of xylitol production by immobilized cells was 21 % higher than free cells.•The maximum xylitol production (7.36 g/L) by immobilized cells was achieved during the third cycle. E. coli has been engineered to produce xylitol, but the production faces bottlenecks in terms of production yield and cell viability. In this study, recombinant E. coli (rE. coli) was immobilized on untreated and treated multiwalled carbon nanotubes (MWCNTs) for xylitol production. The immobilized rE. coli on untreated MWCNTs gave the highest xylitol production (5.47 g L−1) and a productivity of 0.22 g L−1 h−1. The doubling time for the immobilized cells increased up to 20.40 h and was higher than that of free cells (3.67 h). Cell lysis of the immobilized cells was reduced by up to 73 %, and plasmid stability improved by up to 17 % compared to those of free cells. Xylitol production using the optimum parameters (pH 7.4, 0.005 mM and 29 °C) achieved a xylitol production and productivity of 6.33 g L−1 and 0.26 g L−1 h−1, respectively. A seven-cycle repeated batch fermentation was carried out for up to 168 h, which showed maximum xylitol production of 7.36 g L−1 during the third cycle. Hence, this new adsorption immobilization system using MWCNTs is an alternative to improve the production of xylitol.