title: Statistical optimization of cell disruption techniques for releasing intracellular X-prolyl dipeptidyl aminopeptidase from Lactococcus lactis spp. lactis.
abstract: X-prolyl dipeptidyl aminopeptidase (PepX) is an intracellular enzyme from the Gram-positive bacterium Lactococcus lactis spp. lactis NRRL B-1821, and it has commercial importance. The objective of this study was to compare the effects of several cell disruption methods on the activity of PepX. Statistical optimization methods were performed for two cavitation methods, hydrodynamic (high-pressure homogenization) and acoustic (sonication), to determine the more appropriate disruption method. Two level factorial design (2FI), with the parameters of number of cycles and pressure, and Box-Behnken design (BBD), with the parameters of cycle, sonication time, and power, were used for the optimization of the high-pressure homogenization and sonication methods, respectively. In addition, disruption methods, consisting of lysozyme, bead milling, heat treatment, freeze-thawing, liquid nitrogen, ethylenediaminetetraacetic acid (EDTA), Triton-X, sodium dodecyl sulfate (SDS), chloroform, and antibiotics, were performed and compared with the high-pressure homogenization and sonication methods. The optimized values of high-pressure homogenization were one cycle at 130 MPa providing activity of 114.47 mU ml(-1), while sonication afforded an activity of 145.09 mU ml(-1) at 28 min with 91% power and three cycles. In conclusion, sonication was the more effective disruption method, and its optimal operation parameters were manifested for the release of intracellular enzyme from a L. lactis spp. lactis strain, which is a Gram-positive bacterium.
authors.affiliation: Department of Food Engineering, Faculty of Engineering, Pamukkale University, Kinikli, 20020 Denizli, Turkey. Electronic address: drozlemaytekin@gmail.com.
authors.forename: Özlem
authors.initials: Ö
authors.lastname: Üstün-Aytekin
authors.affiliation: Department of Food Engineering, Faculty of Engineering, Pamukkale University, Kinikli, 20020 Denizli, Turkey.
authors.forename: Sevda
authors.initials: S
authors.lastname: Arısoy
authors.affiliation: Department of Genetics and Bioengineering, Faculty of Engineering, Yeditepe University, Atasehir, 34755 Istanbul, Turkey.
authors.forename: Ali Özhan
authors.initials: AÖ
authors.lastname: Aytekin
authors.affiliation: Department of Bioengineering, Faculty of Engineering, Ege University, Bornova, 35100 Izmir, Turkey.
authors.forename: Ece
authors.initials: E
authors.lastname: Yıldız
mesh_terms: D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases / Q000378:metabolism*; D057446:Hydrodynamics; D042541:Intracellular Space / Q000201:enzymology*; D013294:Lactococcus lactis / Q000166:cytology* / Q000201:enzymology; D055595:Mechanical Phenomena; D011312:Pressure; D013010:Sonication; D013223:Statistics as Topic
chemical_list: D004152:Dipeptidyl-Peptidases and Tripeptidyl-Peptidases
keywords: Cell disruption methods; Lactococcus lactis spp. lactis; Sonication; Statistical optimization; X-prolyl dipeptidyl aminopeptidase