Co-production of ethanol and squalene using a Saccharomyces cerevisiae ERG1 (squalene epoxidase) mutant and agro-industrial feedstock

Table 4 Sterol composition, dry weight biomass and squalene titre of YUG37- ERG1 cultured using GJ

DOX	Sterol composition (mg sterol g^-1)				Total	Biomass	Squalene titre
(μg mL^-1)	^a14α-DM	^b14α-M	Ergosterol	Squalene	(mg g^-1)	(g L^-1)	(mg L^-1)
0	1.09 [0.23]	0.47 [0.16]	3.51 [0.83]	0.19 [0.09]	5.25 [0.35]	4.80 [0.28]	0.88 [0.39]
0.025	0.97 [0.46]	0.27 [0.27]	2.64 [0.40]	3.98 [0.68]	7.85 [0.35]	4.50 [0.28]	18.0 [4.18]
0.05	0.73 [0.21]	0.28 [0.17]	2.00 [0.34]	5.14 [0.25]	8.15 [0.21]	2.25 [0.21]	11.5 [0.53]
0.5	0.31 [0.07]	0.09 [0.01]	2.63 [0.48]	5.92 [0.27]	8.95 [0.15]	1.78 [0.11]	10.5 [1.11]
5	0.10 [0.01]	0.01 [0.01]	1.27 [0.15]	7.89 [0.25]	9.28 [0.11]	1.44 [0.04]	11.4 [0.70]
50	—	—	1.31 [0.46]	7.84 [0.25]	9.15 [0.21]	1.45 [0.07]	11.4 [0.20]
**5	—	—	4.34 [0.07]	2.22 [0.28]	6.55 [0.35]	5.40 [0.14]	12.0 [1.83]
**50	—	—	3.80 [0.37]	2.45 [0.02]	6.25 [0.35]	5.20 [0.14]	12.7 [0.24]

All cultures maintained at 20°C in the Bioscreen. Mean values (n = 3 [±SD]); DOX = doxycycline. Maximum squalene content and titre are emboldened. Asterisks indicate sequential production experiments supplemented with additional GJ + DOX after 48 h growth in the absence of DOX.
Strikethrough = not detected.
^a = sum of all 14α-demethylated sterols; ^b = sum of 14α-methylated sterols.

ISSN: 2731-3654