Electrical Retrieval of Living Streptomycete Spores Using a Potential-Controlled ITO Electrode

Abstract

The purpose of this study was to develop a novel electrical retrieval method for living spores of streptomycetes. Five strains of deep-sea Streptomyces sp. and typical strain Streptomyces albus suspended in 1/20 artificial seawater (1/20ASW) were selectively attached to an indium tin oxide/glass (ITO) working electrode region to which a −0.2 V vs. Ag/AgCl constant potential was applied for 24 h. Spores of all six streptomycetes produced either short fibrous or membranous materials and attached to the ITO electrode region. A ±20 mV vs. Ag/AgCl, 12 MHz sine-wave potential was further applied for another 1 h to the deep-sea Streptomyces sp. ST.28 spores on the ITO electrode and colony-forming units increased 3.5 fold after 3 day cultivation compared with controls. The ST.28 spores almost completely lost the ability to adhere to the potential-applied ITO electrode when dispersed in Mg²⁺ free 1/20ASW. We succeeded in the attachment and cultivation of specifically positioned single ST.28 spores on an ITO microelectrode surface with −0.2 V vs. Ag/AgCl potential application. A combination of micropatterning techniques for a living single streptomycete spore on the ITO electrode and omics technologies holds potential for new bioactive compound screening concepts and applications.