AUTHOR=Zheng Xueyun , Zhang Yimin , Liu Xiaoxiao , Li Cheng , Lin Ying , Liang Shuli 

TITLE=High-Level Expression and Biochemical Properties of A Thermo-Alkaline Pectate Lyase From Bacillus sp. RN1 in Pichia pastoris With Potential in Ramie Degumming

JOURNAL=Frontiers in Bioengineering and Biotechnology

VOLUME=8

YEAR=2020

URL=https://www.frontiersin.org/journals/bioengineering-and-biotechnology/articles/10.3389/fbioe.2020.00850

DOI=10.3389/fbioe.2020.00850

ISSN=2296-4185

ABSTRACT=<p>Pectate lyases play an essential role in textiles, animal feed, and oil extraction industries. <italic>Pichia pastor</italic>is can be an ideal platform for pectate lyases production, and BspPel (a thermo-alkaline pectate lyase from <italic>Bacillus</italic> sp. RN1) was overexpressed by combined strategies, reaching 1859 U/mL in a 50 L fermentator. It displayed the highest activity at 80°C, and maintained more than 60% of the activity between 30 and 70°C for 1 h. It showed an optimal pH of 10.0, and exhibited remarkable stability over a wider pH range (3.0-11.0), retaining more than 80.0% of enzyme activity for 4 h. The <italic>K</italic><sub><italic>m</italic></sub> and <italic>k</italic><sub><italic>cat</italic></sub> of BspPel on PGA (polygalacturonic acid) was 2.19 g L<sup>–1</sup> and 116.1 s<sup>–1</sup>, respectively. The activity was significantly enhanced by Ca<sup>2+</sup>, Mn<sup>2+</sup>, and Cu<sup>2+</sup>, and a slight increase was observed with the addition of Ba<sup>2+</sup> and Mg<sup>2+</sup>. Scanning electron microscope was used to show the degumming efficiency of BspPel on ramie fibers. The loss weight was 9.2% when treated with crude enzyme supernatant and 20.8% when treated with the enzyme-chemical method, which was higher than the 14.2% weight loss in the positive control treated with 0.5% (w/v) NaOH alone. In conclusion, BspPel could be a good candidate for the ramie degumming industry.</p>