Edible oils from microalgae: insights in TAG accumulation
Klok, A.J. ; Lamers, P.P. ; Martens, D.E. ; Draaisma, R.B. ; Wijffels, R.H. - \ 2014
Trends in Biotechnology 32 (2014)10. - ISSN 0167-7799 - p. 521 - 528.
diatom phaeodactylum-tricornutum - fatty-acid biosynthesis - chlamydomonas-reinhardtii - nitrogen starvation - triacylglycerol accumulation - diacylglycerol acyltransferase - lipid-metabolism - nuclear transformation - biofuel production - genes
Microalgae are a promising future source for sustainable edible oils. To make microalgal oil a cost-effective alternative for common vegetable oils, increasing TAG productivity and TAG content are of high importance. Fulfilling these targets requires proper understanding of lipid metabolism in microalgae. Here, we provide an overview of our current knowledge on the biology of TAG accumulation as well as the latest developments and future directions for increasing oil production in microalgae, considering both metabolic engineering techniques and cultivation strategies.
A transcriptional study of acidogenic chemostat cells of Clostridium acetobutylicum - Cellular behavior in adaptation to n-butanol
Schwarz, K.M. ; Kuit, W. ; Grimmler, C. ; Ehrenreich, A. ; Kengen, S.W.M. - \ 2012
Journal of Biotechnology 161 (2012)3. - ISSN 0168-1656 - p. 366 - 377.
fatty-acid biosynthesis - 2-component signal-transduction - organic-solvent tolerance - response regulator yycf - beijerinckii ncimb 8052 - gram-negative bacteria - escherichia-coli - bacillus-subtilis - lipid-composition - gene-expression
To gain more insight into the butanol stress response of Clostridium acetobutylicum the transcriptional response of a steady state acidogenic culture to different levels of n-butanol (0.25-1%) was investigated. No effect was observed on the fermentation pattern and expression of typical solvent genes (aad, ctfA/B, adc, bdhA/B, ptb, buk). Elevated levels of butanol mainly affected class I heat-shock genes (hrcA, grpE, dnaK, dnaJ, groES, groEL, hsp90), which were upregulated in a dose- and time-dependent manner, and genes encoding proteins involved in the membrane composition (fab and fad or glycerophospholipid related genes) and various ABC-transporters of unknown specificity. Interestingly, fab and fad genes were embedded in a large, entirely repressed cluster (CAC1988-CAC2019), which inter alia encoded an iron-specific ABC-transporter and molybdenum-cofactor synthesis proteins. Of the glycerophospholipid metabolism, the glycerol-3-phosphate dehydrogenase (glpA) gene was highly upregulated, whereas a glycerophosphodiester ABC-transporter (ugpAEBC) and a phosphodiesterase (ugpC) were repressed. On the megaplasmid, only a few genes showed differential expression, e.g. a rare lipoprotein (CAP0058, repressed) and a membrane protein (CAP0102, upregulated) gene. Observed transcriptional responses suggest that C. acetobutylicum reacts to butanol stress by induction of the general stress response and changing its cell envelope and transporter composition, but leaving the central catabolism unaffected