Reducing glucoamylase usage for commercial-scale ethanol production from starch using glucoamylase expressing Saccharomyces cerevisiae

Bioresources and Bioprocessing

Table 2 Physiological characteristics of the glucoamylase producing strains and the parental strain

		CCTCC M94055	CIBTS1518	CIBTS1519	CIBTS1520	CIBTS1521	CIBTS1522
Ethanol conc. (%, v/v)	12	+ + +	+ + +	+ + +	+ + +	+ + +	+ + +
	14	+	−	−	−	+	+
	16	−	−	−	−	−	−
Glucose conc. (g/L)^a	5	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +
	150	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +
	300	+ + / + + +	+ + / + +	+ + / + +	+ + / + +	+ + / + +	+ + / + +
	400	+ / +	−/ + +	−/−	−/−	−/−	+ / +
NaCl conc (g/L)^a	5	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +	+ + + / + + +
	50	+ / + +	+ / +	+ / +	+ / +	+ / + +	+ / +
	150	−/−	−/−	−/−	−/−	−/ +	−/−
	200	−/−	−/−	−/−	−/−	−/−	−/−
Temp. ℃^b	57	+ + +					+ + +
	59	+ + +					+ + +
	61	+ + +					+ + +
	63	+					+ +
	65	−					−
pH^b	2.0	−					−
	3.0	+ +					+ +
	4.0	+ + +					+ + +
	5.0	+ + +					+ + +
Ethanol titer from corn starch (%, v/v)^c		21.6	22.5	22.1	22.1	21.7	22.6

+ + + , obvious growth; + + , moderate growth; + , little growth; −, no growth
^aThe results of days 1 and 7 are separated by the “/” symbol
^bThe temperature and pH tolerance test was only conducted using the control and CIBTS1522 strains
^cThe measurements represent the mean of three repeats