Effects of shear stress and mass transfer on chitinase production by Paenibacillus sp. CHE-N1

Production of the biocontrol agent Pantoea agglomerans PBC-1 in a stirred tank reactor by batch and fed-batch cultures

“…These parameters influence the volumetric mass transfer coefficient, K L a, an experimental factor extremely important in aerobic cultures with severe oxygen demands. With the intention of understanding the impact of mass transfer and mixing in the performance of stirred bioreactors, different reports have appeared in the literature (Puthli et al 2005;Cascaval et al 2006;Hadjiev et al 2006;Puthli et al 2006;Raposo and Lima-Costa 2006;Fujasová et al 2007;Kao et al 2007;Littlejohns and Daugulis 2007;Pollard et al 2007;Potumarthi et al 2007). …”

Production of chitinolytic enzymes by a strain (BM17) of Paenibacillus pabuli isolated from crab shells samples collected in the east sector of central Tyrrhenian Sea

“…In addition, although very little details are available on the chitinase production by Paenibacilli, the production of strain BM17 seems to be rather abundant if compared with the literature [30] and merits further investigations.…”

Specific oxygen uptake rate as indicator of cell response of Rhodococcus erythropolis cultures to shear effects

“…causing a specified level of damage over a given exposure time or under certain operating conditions. Despite the fact that hydrodynamic forces influence the behaviour of cells in suspension has been established long ago (Feugier et al, 2005;Garcia et al, 2005;Garcia et al, 2001;Han and Yuan, 2004;Hao et al, 2009;Kao et al, 2007;Legazpi et al, 2009;Merchuk, 1991;Yepez and Maugeri, 2005), there is a lack of proposals to describe this phenomenon together with the most appropriate measuring technique. However, it is an important challenge to integrate the physiological conditions of the cells and the hydrodynamics of the medium together for the development and scale-up of bioprocesses.…”

“…Shear effects can have many manifestations and different parameters have been employed as indicators of shear response of cells such as modification of morphology Peña et al, 2000), alteration of the metabolism and the productivity, which can affect the rates of growth, production and consumption of nutrients (Kao et al, 2007;Kunas and Papoutsakis, 1990;Meijer et al, 1994), the change of rheology for nonNewtonian broths (Rosa et al, 2005;Campesi et al, 2009) and loss of viability, necrosis and cell death (AI-Rubeai and Singht, 1998;Garcia-Ochoa et al, 2013;Hao et al, 2009;Sahoo et al, 2006;Wang et al, 1994). Although the previously cited stress indicators can be used to have an idea about the operating conditions that may damage or produce changes into the cell culture, it would be interesting to determine a critical value of some parameter or magnitude (stirrer speed, shear rate, shear stress, cumulative energy dissipated, etc.)…”