title: Improved production of live cells of Lactobacillus rhamnosus by continuous cultivation using glucose-yeast extract medium.
abstract: In this study, the growth kinetics of Lactobacillus rhamnosus and lactic acid production in continuous culture were assessed at a range of dilution rates (0.05 h(-1) to 0.40 h(-1)) using a 2 L stirred tank fermenter with a working volume of 600 ml. Unstructured models, predicated on the Monod and Luedeking-Piret equations, were employed to simulate the growth of the bacterium, glucose consumption, and lactic acid production at different dilution rates in continuous cultures. The maximum specific growth rate of L. rhamnosus, mu-max, was estimated at 0.40 h(-1), and the Monod cell growth saturation constant, Ks, at approximately 0.25 g/L. Maximum cell viability (1.3 x 10(10) CFU/ml) was achieved in the dilution rate range of D = 0.28 h(-1) to 0.35 h(-1). Both maximum viable cell yield and productivity were achieved at D = 0.35 h(-1). The continuous cultivation of L. rhamnosus at D = 0.35 h(-1) resulted in substantial improvements in cell productivity, of 267% (viable cell count) that achieved via batch cultivation.
authors.affiliation: Laboratory of Enzyme and Microbial Technology, Institute of Bioscience Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
authors.forename: Liew Siew
authors.initials: LS
authors.lastname: Ling
authors.forename: Rosfarizan
authors.initials: R
authors.lastname: Mohamad
authors.forename: Raha Abdul
authors.initials: RA
authors.lastname: Rahim
authors.forename: Ho Yin
authors.initials: HY
authors.lastname: Wan
authors.forename: Arbakariya Bin
authors.initials: AB
authors.lastname: Ariff
mesh_terms: D003470:Culture Media; D005285:Fermentation; D007700:Kinetics; D052201:Lacticaseibacillus rhamnosus / Q000254:growth & development* / Q000378:metabolism; D050296:Microbial Viability; D008954:Models, Biological; D015233:Models, Statistical
chemical_list: D003470:Culture Media