title: UvrA expression ofLactococcus lactisNZ9000 improve multiple stresses tolerance and fermentation of lactic acid against salt stress.
abstract: Lactococcus lactisis subjected to several stressful conditions during industrial fermentation including oxidation, heating and cooling, acid, high osmolarity/dehydration and starvation. DNA lesion is a major cause of genetic instability inL. lactisthat usually occurs at a low frequency, but it is greatly enhanced by environmental stresses. DNA damages produced by these environmental stresses are thought to induce DNA double-strand breaks, leading to illegitimate recombination. Nucleotide excision repair (NER) protein UvrA suppresses multiple stresses-induced illegitimate recombination. UvrA protein can survive a coincident condition of environmental harsh conditions, multiple stress factors supposedly encountered in the host and inducing UvrA inL. lactis. In this study the expression of UvrA and growth performance and viability of control strainL. lactisVector andrecombinant strain L. lactisUvrA under multiple stress conditions were determined. The recombinants strain had 30.70 and 52.67% higher growth performances when subjected to acidic and osmotic stresses conditions. In addition, theL. lactisUvrA strain showed 1.85-, 1.65-, and 2.40-fold higher biomass, lactate production, and lactate productivity, compared with the corresponding values forL. lactisVector strain during the osmotic stress. Results demonstrated NER system is involved in adaptation to various stress conditions and suggested that cells with a compromised UvrA as DNA repair system have an enhanced protection behavior inL. lactisNZ9000 against DNA damage.
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu 214122 People's Republic of China.|School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122 People's Republic of China.
authors.forename: Taher Khakpour
authors.initials: TK
authors.lastname: Moghaddam
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu 214122 People's Republic of China.|School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122 People's Republic of China.
authors.forename: Juan
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Key Laboratory of Industrial Biotechnology, Ministry of Education, Jiangnan University, Wuxi, Jiangsu 214122 People's Republic of China.|School of Biotechnology, Jiangnan University, 1800 Lihu Road, Wuxi, Jiangsu 214122 People's Republic of China.
authors.forename: Guocheng
authors.initials: G
authors.lastname: Du
keywords: Lactate productivity; Lactococcus lactis NZ9000; Multiple stresses; UvrA expression