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Updated: Feb 7, 2026

Scalable Isolation and Purification of Extracellular Vesicles from Escherichia coli and Other Bacteria
Published on: October 13, 2021
Extracellular release of recombinant alpha-amylase from Escherichia coli using pulsed electric field
Satoshi Shiina1, Takayuki Ohshima, Masayuki Sato
1Department of Biological and Chemical Engineering, Faculty of Engineering, Gunma University, 1-5-1 Tenjin-cho, Kiryu, Gunma, 376-8515, Japan. tohshima@bce.gunma-u.ac.jp
Abstract:
It is difficult for Escherichia coli to secrete products such as recombinant enzymes, because the Gram-negative bacterium has a double membrane structure and so some of the products are accumulated in a periplasmic space. In this study, we demonstrated that recombinant alpha-amylase can be released from recombinant E. coli HB101/pHI301A during cultivation by applying a pulsed electric field (PEF). When a PEF (12 kV, 2 Hz) was applied for 30 min with an interval of 30 min from the point of OD660=0.7, the amount of released alpha-amylase was about 30% of the total amount of alpha-amylase produced in the cells. As a result of SDS-PAGE and activity staining analyses, it was confirmed that the released proteins were not all of the intracellular proteins, and the alpha-amylase, which was identical with intracellular alpha-amylase, was released by applied PEF cultivation. PEF treatment could be useful for easy release of periplasmic protein with selectivity.
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