Open AccessProduction of paramylon, a β‐1,3‐glucan, by heterotrophic growth of Euglena gracilis on potato liquor in fed‐batch and repeated‐batch mode of cultivation
Author(s) -
Šantek Bozˇidar,
Friehs Karl,
Lotz Martin,
Flaschel Erwin
Publication year - 2012
Publication title -
engineering in life sciences
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.547
H-Index - 57
eISSN - 1618-2863
pISSN - 1618-0240
DOI - 10.1002/elsc.201100025
Subject(s) - euglena gracilis , biomass (ecology) , food science , starch , heterotroph , yield (engineering) , pulp and paper industry , batch processing , bioreactor , chemistry , process (computing) , biology , botany , bacteria , biochemistry , agronomy , materials science , computer science , genetics , chloroplast , metallurgy , gene , engineering , operating system , programming language
Recently, it had been shown that Euglena gracilis was able to grow heterotrophically not only on synthetic media, but also on media based on potato liquor. Supplementation with glucose in both cases led to the accumulation of paramylon, a β‐1,3‐glucan. Thus, such a process may yield a valuable product accompanied by the revaluation of an otherwise annoying waste stream of the potato‐starch industry. Actually, process strategies have been evaluated in order to optimise the concentration of paramylon obtained at the end of the cultivation process. Therefore, cultivation processes based on fed‐batch and in particular repeated‐batch strategies have been studied. It is shown that repeated‐batch operation maybe particularly suited for such a process since E. gracilis seems to adapt gradually to the cultivation medium so that the concentration of media components may be increased step by step. Repeated‐batch cultivation of E. gracilis leads to biomass concentrations in access of 20 g/L with a consistent paramylon mass fraction of about 75%. Cultivations have been carried out at an operating temperature of 27.5°C. As had been found earlier already, pH control is not required during cultivation. On the basis of these results it is clear that repeated‐batch cultivation represent a simple and economic way for the production of paramylon by heterotrophic cultivation of E. gracilis .