Mechanical stress as pretreatment for the separation of exopolysaccharides (eps) producing bacterial starter cultures

F. Häffele*, H. Nirschl, Karlsruhe Institute of Technology (KIT); S. Mende, D. Jaros, H. Rohm, Technical University Dresden, Germany

Bacterial starter cultures such as lactic acid bacteria (LAB) are essential for the manufacturing of fermented foods. The industrial production of these starter cultures takes place at specific manufacturing conditions with regard to temperature, pH and nutrient composition. Due to the plurality of highly specialized starter cultures, an individual adaption of the fermentation process is necessary. However, changing fermentation parameters leads to altered separation properties and has thereby a huge influence on the subsequent separation process.

Goal of this project is the investigation of the effects of an energy input generated by shearing on the sedimentation properties of different EPS producing lactic acid bacteria. Furthermore a guideline for the determination of the best pretreatment and centrifugal parameters of different EPS-producing starter cultures shall be developed.

Shear forces were generated either with a rotor-stator system (ULTRA-TURRAX®) or with a high pressure homogenizer (EmulsiFlex-C5). Sedimentation velocity and sediment compression were obtained from measurements with an analytical centrifuge (LUMiSizer®). It was shown that shearing EPS-producing starter cultures may result in...

Session: L14 - Slurry Pretreatment by Shearing, Classification, pH-shift
Day: 15 March 2018
Time: 13:00 - 14:15 h

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