Lipid production in Porphyridium cruentum grown under different culture conditions.
Autotrophic growth of Porphyridium cruentum under 18:12 h and 12:12 h light:dark cycles showed the maximum cell concentration of 2.1 g-dry wt./L, whereas the specific growth rate, 0.042 (1/h), at 18:6 h is faster than that of 12:12 h, 0.031 (1/h), respectively. The highest lipid accumulation level, 19.3 (%, w/w), was achieved at 12:12 h cycle. Under dark cultivation condition with 10 g/L of glucose, the lipid accumulation in the cell was 10.9 (%, w/w), whereas the heterotrophic growth with glycerol as the carbon resource showed low level of cell concentration and lipid production, compared to that of glucose. The glucose was decided to be a suitable carbon resource for the heterotrophic growth of P. cruentum. The lipids from P. cruentum seemed be feasible for biodiesel production, because over 30% of the lipid was C16-C(18:1). The cultivation time and temperature were important factors to increase the maximum cell concentration. Extending the cultivation time helps maintain the maximum cell concentration, and higher lipid accumulation was achieved at 25 degrees C, compared to 35 degrees C. The fed-batch cultures showed that, under the light condition, the specific production rate was slightly decreased to 0.4% lipid/g-dry wt./day at the later stage, whereas, under the dark condition, the specific production rate was maintained to be a maximum value of 1.1% lipid/g-dry wt./day, even in the later stage of cultivation. The results indicate that the heterotrophic or 12:12 h cyclic mixotrophic growth of P. cruentum could be used for the production of biodiesel in long-term fed-batch cultivation of P. cruentum.
Oh
Sung Ho
SH
College of Bioscience and Biotechnology, Department of Biomaterials Engineering, Kangwon National University, Chunchon 200-701, Republic of Korea.
Han
Jae Gun
JG
Kim
Young
Y
Ha
Ji Hye
JH
Kim
Seung Seop
SS
Jeong
Myoung Hoon
MH
Jeong
Hyang Suk
HS
Kim
Na Young
NY
Cho
Jeong Sub
JS
Yoon
Won Byong
WB
Lee
Shin Young
SY
Kang
Do Hyung
DH
Lee
Hyeon Yong
HY
D056804:Biofuels; D019149:Bioreactors / Q000382:microbiology*; D018929:Cell Culture Techniques / Q000379:methods*; D049109:Cell Proliferation; D002470:Cell Survival; D050356:Lipid Metabolism / Q000502:physiology*; D044665:Porphyridium / Q000145:classification / Q000254:growth & development* / Q000378:metabolism*; D013045:Species Specificity
D056804:Biofuels