# Charge Transport in Bifidobacterium animalis subsp. lactis BB-12 under the various Atmosphere

## TL;DR

This study investigates how relative humidity affects the electrical properties of Bifidobacterium animalis subsp. lactis BB-12, revealing humidity's significant impact on conductivity, hysteresis, and surface charge characteristics.

## Contribution

First analysis of humidity effects on the electrical behavior of Bifidobacterium animalis subsp. lactis BB-12, highlighting the role of water molecules in charge transport mechanisms.

## Key findings

- Electrical conductivity increases by six orders of magnitude at 75% RH.
- Humidity influences hysteresis in I-V characteristics.
- Surface charge is negative, with electrons as charge carriers.

## Abstract

The influence of relative humidity (RH) on quasistatic current-voltage ${(I-V)}$ characteristics of Bifidobacterium animalis subsp. lactis BB-12 thin layers have been studied for the first time. The value of electrical conductivity in 75$ \%$ RH was found to be in the order of 10$^{-7}$ (ohm cm)$^{-1}$ which was 10$^{6}$ orders of magnitude higher than that observed in dry atmosphere. Here we also demonstrated that RH played a key role in hysteresis behaviour of the measured ${(I-V)}$ characteristics. FTIR measurements showed that under water moisture environment the associated bonds for amine and carboxyl group were greatly strengthened that was the source of number of free charge carries after ionization. The type of surface charge of Bifidobacterium animalis subsp. lactis BB-12 was found to be negative by zeta potential measurements, claiming that electrons were the charge carriers.