title: Low intensity ultrasound increases the fermentation efficiency of Lactobacillus casei subsp.casei ATTC 39392.
abstract: L-Lactic acid (L-LA) is one of the microbial products with several applications and its production efficiency is so important. In the present study, we have been exploring application of low intensity ultrasound technology to improve the metabolic activity for L-lactic acid production by Lactobacillus casei in different mediums. L-LA, biomass production and substrate (protein) consumption were measured as parameters of fermentation yield. L-LA and protein contents were determined using the titratable acidity and the biuret method respectively. Spectrophotometry (OD600nm) was used for measuring cell growths. L-LA, biomass production and protein consumption considered as dependent variables, but the amplitude of waves (20%, 40% and 60%), waves duration (15, 30, 45 s) and add of peptone (2, 6 and 10 g/l) as independent variables. The results showed that L-LA, biomass production and substrate consumption significantly increased (≈25%). Optimum conditions for biomass production was amplitude of 60%, 15s exposure time and 10 g/l peptone, while for acid lactic production and substrate consumption was 40%, 30s and 6g/l peptone, respectively. Flowcytometry analysis also showed that sonication led to increasing cell membrane permeability. This observation shows low intensity ultrasound as a potential parameter in the improvement of metabolic activity of L. casei.
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Tabriz University, Tabriz, Iran.
authors.forename: Behnaz Dahri
authors.initials: BD
authors.lastname: Dahroud
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Tabriz University, Tabriz, Iran.
authors.forename: Reza Rezai
authors.initials: RR
authors.lastname: Mokarram
authors.affiliation: Department of Food Science and Technology, Faculty of Agriculture, Tabriz University, Tabriz, Iran.
authors.forename: Mahmoud Sowti
authors.initials: MS
authors.lastname: Khiabani
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Hamed
authors.initials: H
authors.lastname: Hamishehkar
authors.affiliation: Biotechnology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
authors.forename: Abed Zahedi
authors.initials: AZ
authors.lastname: Bialvaei
authors.affiliation: Immunology Research Center, Tabriz University of Medical sciences, Tabriz, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Yousefi
authors.affiliation: Drug Applied Research Center, Tabriz University of Medical Sciences, Tabriz, Iran. Electronic address: Kafilhs@tbzmed.ac.ir.
authors.forename: Hossein Samadi
authors.initials: HS
authors.lastname: Kafil
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D018533:Biomass; D002463:Cell Membrane Permeability; D005285:Fermentation; D019344:Lactic Acid / Q000096:biosynthesis; D007780:Lacticaseibacillus casei / Q000166:cytology / Q000254:growth & development / Q000378:metabolism*; D000069453:Ultrasonic Waves
chemical_list: D001426:Bacterial Proteins; D019344:Lactic Acid
keywords: L-LA production; Lactobacillus casei; Low intensity ultrasound