Enhancing the growth of thermophilic Bacillus licheniformis YYC4 by low-intensity fixed-frequency continuous ultrasound

Chunhua Dai; Zhenzhen Shu; Xueting Xu; Pengfei Yan; Mokhtar Dabbour; Benjamin Kumah Mintah; Liurong Huang; Ronghai He; Haile Ma

doi:10.1016/j.ultsonch.2023.106611

Enhancing the growth of thermophilic Bacillus licheniformis YYC4 by low-intensity fixed-frequency continuous ultrasound

Ultrason Sonochem. 2023 Nov:100:106611. doi: 10.1016/j.ultsonch.2023.106611. Epub 2023 Sep 23.

Authors

Chunhua Dai¹, Zhenzhen Shu², Xueting Xu², Pengfei Yan², Mokhtar Dabbour³, Benjamin Kumah Mintah⁴, Liurong Huang¹, Ronghai He⁵, Haile Ma¹

Affiliations

¹ School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; Institute of Food Physical Processing, Jiangsu University, Zhenjiang 212013, China.
² School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China.
³ Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, Benha University, P.O. Box 13736, Moshtohor, Qaluobia, Egypt.
⁴ CSIR - Food Research Institute, P.O. Box M20, Accra, Ghana.
⁵ School of Food and Biological Engineering, Jiangsu University, Zhenjiang 212013, China; Institute of Food Physical Processing, Jiangsu University, Zhenjiang 212013, China. Electronic address: heronghai1971@126.com.

Abstract

The effect of low-intensity fixed-frequency continuous ultrasound (LIFFCU) on the growth of Bacillus licheniformis YYC4 was investigated. The changes in morphology and activity of the organism, contributing to the growth were also explored. Compared with the control, a significant increase (48.95%) in the biomass of B. licheniformis YYC4 (at the logarithmic metaphase) was observed following the LIFFCU (28 kHz, 1.5 h and 120 W (equivalent to power density of 40 W/L)) treatment. SEM images showed that ultrasonication caused sonoporation, resulting in increased membrane permeability, evidenced by increase in cellular membrane potential, electrical conductivity of the culture, extracellular protein and nucleic acid, and intracellular Ca²⁺ content. Furthermore, LIFFCU action remarkably increased the extracellular protease activity, volatile components of the culture medium, microbial metabolic activity, and spore germination of the strain. Therefore, LIFFCU could be used to efficiently promote the growth of targeted microorganisms.

Keywords: Bacillus licheniformis YYC4; Cell membrane permeability; Low-intensity ultrasound; Microbial metabolism; Spore germination.

MeSH terms

Bacillus licheniformis*
Bacterial Proteins
Spores, Bacterial / metabolism

Substances

Bacterial Proteins