Development and application of a biocatalyst-filter reactor for the continuous production of caseinate hydrolysate surfactants

Publikations-Art

Zeitschriftenbeitrag (peer-reviewed)

Autoren

Ewert, J.; Horstmann, G.; Glück, C.; Claaßen, W.; Stressler, T.; Fischer, L.

Erscheinungsjahr

2018

Veröffentlicht in

Process Biochemistry

Verlag

Elsevier

DOI

10.1016/j.procbio.2018.06.004

A novel continuous process for enzymatic production of sodium caseinate hydrolysates with a low degree of hydrolysis (DH) and increased interfacial behaviour was developed. Retention of free peptidase in the reactor (separation of the peptidase from the product via an ultra-filtration membrane) was not possible because the peptidase used (thermolysin-like peptidase from Geobacillus stearothermophilus; Sternzym BP 25201; 34 kDa, approximately 4.3 nm) was smaller than the hydrolysate product (up to 90 µm). Thus, the peptidase was immobilized on macroporous particles (Sepabeads EC-EP/M; 200 – 500 µm) and applied for the process consisting of a stirred reactor vessel and a metal filter (150 µm) as the separation unit. A consistent DH of 2.2–2.6 % was obtained by adding about 1/3 of the initial peptidase activity per day or adjusting the residence time. This DH resulted in improved foam and emulsion behaviours (foam stability increased to 139 ± 2.3 %; emulsion stability increased to 162 ± 9 %) of the filtrate compared to substrate and was like a hydrolysate produced in a batch hydrolysis using the free enzyme. However, the continuous process was superior to the batch process because it resulted in an increased space-time yield (155 %) and enzyme productivity (695 %).