Influence of Low-Intensity Ultrasound on <i>ε</i>-Polylysine Production: Intracellular ATP and Key Biosynthesis Enzymes during <i>Streptomyces albulus</i> Fermentation
Jiahui Xiang,
Mokhtar Dabbour,
Xianli Gao,
Benjamin Kumah Mintah,
Yao Yang,
Wenbin Ren,
Ronghai He,
Chunhua Dai,
Haile Ma
Affiliations
Jiahui Xiang
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
Mokhtar Dabbour
Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, Benha University, Qaluobia P.O. Box 13736, Egypt
Xianli Gao
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
Benjamin Kumah Mintah
Council for Scientific and Industrial Research—Food Research Institute, Accra P.O. Box M20, Ghana
Yao Yang
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
Wenbin Ren
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
Ronghai He
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
Chunhua Dai
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
Haile Ma
School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang 212013, China
The effect of low-intensity sonication treatment on cell growth, ε-polylysine (ε-PL) yield and its biological mechanism were investigated, using a 3-L-jar fermenter coupled with an in situ ultrasonic slot with a Streptomyces albulus strain SAR 14-116. Under ultrasonic conditions (28 kHz, 0.37 W cm−2, 60 min), a high biomass of SAR 14-116 and concentration of ε-PL were realized (i.e., they increased by 14.92% and 28.45%, respectively) when compared with a control. Besides this, ultrasonication increased the mycelia viability and intracellular ATP as well as activities of key enzymes involved in the ε-PL biosynthesis pathway, resulting in an improvement in the production of ε-PL. Data on qRT-PCR revealed that ultrasonication also affected the gene expression of key enzymes in the ε-PL biosynthesis pathway, including ε-PL synthetase (PLS). These outcomes provided the basis for understanding the effects of ultrasound-assisted fermentation on the stimulation of metabolite production and fermentation procedure in a fermenter.