Xm. Shi et al., Production of biomass and lutein by Chlorella protothecoides at various glucose concentrations in heterotrophic cultures, PROCESS BIO, 34(4), 1999, pp. 341-347
The influence of initial glucose concentrations on the production of biomas
s and lutein by Chlorella protothecoides CS-41 was investigated in batch cu
ltures using both shake flasks and fermenters. The maximum biomass concentr
ation increased from 4.9 to 31.2 g litre(-1) dry cells with an increase in
initial glucose concentration from 10 to 80 g litre(-1). An even higher ini
tial glucose concentration (100 g litre(-1)) resulted in a lower biomass co
ncentration, a lower specific growth rate, a lower growth yield coefficient
and a considerably longer lag phase, which might be due to substrate inhib
ition. The initial glucose level also had a significant effect on the produ
ction of lutein. In a 3.7-litre fermenter an increase in lutein production
from 19.39 to 76.56 mg litre(-1) was obtained with an increase in initial g
lucose concentration from 10 to 40 g litre(-1), within which range, lutein
yield coefficient was constant (Y-Itn = 1.90 +/- 0.02 mg g(-1)). A simple s
ubstrate inhibition model was developed, which fitted the experimental data
better than the classical Haldane model. A group of time-dependent kinetic
models for algal cultivation in fermenters were also constructed, which we
re in good agreement with the experimental results and could be employed to
predict the production of biomass and lutein, and the consumption of gluco
se in fermenter cultures. (C) 1999 Elsevier Science Ltd. All rights reserve
d.