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

Table 1 Phenotypic sterol analysis of YUG37 parent and YUG37- ERG1 mutant

DOX		Sterol composition (mg sterol g^-1)				Total	Biomass	Squalene titre
(μg mL^-1)	Strain	^a14α-DM	^b14α-M	Ergosterol	Squalene	(mg g^-1)	(g L^-1)	(mg L^-1)
0	YUG37	1.45 [0.27]	0.33 [0.03]	3.27 [0.39]	0.16 [0.08]	5.31 [0.19]	3.75 [0.35]	0.50 [0.11]
	YUG37- *ERG1*	1.51 [0.29]	0.39 [0.07]	3.08 [029]	0.40 [0.03]	5.28 [0.24]	4.55 [0.21]	1.76 [0.02]
0.025	YUG37	1.30 [0.16]	0.20 [0.06]	3.09 [0.35]	0.17 [0.13]	4.75 [0.02]	4.25 [0.21]	0.55 [0.31]
	YUG37- *ERG1*	1.55 [0.09]	0.40 [0.03]	2.43 [0.08]	3.57 [0.20]	7.88 [0.31]	4.30 [0.28]	15.04 [1.42]
0.05	YUG37	1.47 [0.22]	0.26 [0.03]	3.03 [0.14]	0.30 [0.04]	4.98 [0.19]	3.90 [0.14]	1.23 [0.03]
	YUG37- *ERG1*	0.78 [0.10]	0.40 [0.08]	2.20 [0.09]	4.24 [0.30]	7.55 [0.33]	2.50 [0.28]	10.31 [0.79]
0.5	YUG37	1.36 [0.22]	0.24 [0.06]	2.79 [0.32]	0.23 [0.06]	4.77 [0.30]	3.95 [0.07]	1.02 [0.14]
	YUG37- *ERG1*	0.45 [0.01]	0.17 [0.02]	1.58 [0.12]	6.75 [0.20]	8.96 [0.06]	1.75 [0.21]	11.93 [1.27]
5	YUG37	1.54 [0.29]	0.29 [0.06]	3.06 [0.42]	0.20 [0.10]	5.03 [0.11]	3.60 [0.42]	0.57 [0.12]
	YUG37- *ERG1*	0.21 [0.04]	0.08 [0.04]	1.49 [0.02]	7.66 [0.01]	9.45 [0.08]	1.48 [0.11]	11.30 [0.82]
50	YUG37	1.21 [0.23]	0.23 [0.01]	2.93 [0.26]	0.14 [0.06]	4.63 [0.27]	3.75 [0.35]	0.59 [0.05]
	YUG37- *ERG1*	0.11 [0.03]	0.02 [0.01]	1.50 [0.03]	7.85 [0.02]	9.48 [0.10]	1.39 [0.12]	10.87 [0.93]

All cultures grown at 30°C, 180 rpm for 48 h on YPD medium. Mean values (n = 3 [±SD]); DOX = doxycycline. Maximum squalene content and yield are emboldened.
^a = sum of all 14α-demethylated sterols; ^b = sum of 14α-methylated sterols.

ISSN: 2731-3654