Table 4.

Fermentation process employed in ethanol production from different feedstocks.

Feedstock	Initial sugar (g/L)	Fermentation mode	Processing/techniques	Microorganisms	Temperature (°C)	pH	Agitation rate (rpm)	Time (h)	Ethanol concentration (g/L)	Productivity (g/L/h)	Ethanol yield (%)	Reference
Sugarcane juice	200	Batch	Juice was supplemented with sucrose	K. marxianus DMKU 3-1042	40	5.0	300	42–96	67.9	1.42	60.4	[59]
	166	Batch	Recycling of yeast	P. kudriavzevii	40	5.5	150	24	71.9	4.00	—	[26]
	173	Repeated batch	Immobilization of cells on sugarcane pieces	S. cerevisiae	30	—	—	32	89.73	2.48	—	[56]
	220	Batch	Coculture of immobilized cells on thin-shell silk cocoon	K. marxianus DMKU 3-1042 and S. cerevisiae M30	37–40	5.0	150	72	77.3–81.4	1.07–1.1	80.23–86.1	[126]
	180	Continuous	Immobilization of cells on chrysotile	Strains of Saccharomyces sp.	30	5.0	—	117	13.3–19.4	—	80.4–97.3	[127]
	200	Continuous	Recycling of cells was done in a tower reactor	S. cerevisiae IR-2	30	—	130	72	90	18	99	[128]
Sweet sorghum juice	190	Fed-batch	Juice was supplemented with 0.5% ammonium sulphate	S. cerevisiae TISTR 5048	30	—	Static	108	116.62–120.28	1.08–1.11	94.12–96.8	[44]
	240–320	Batch	Juice was adjusted with sucrose or molasses for very high gravity fermentation	S. cerevisiae NP01	30	4.9	Static	40–72	120.68	2.01	99.8	[96]
	—	Batch	Immobilization on Ca-alginate	S. cerevisiae CICC 1308	37	5.0	200	11	—	—	93.24	[104]
Watermelon juice	183–409	Batch	Juice was supplemented with molasses	Dried yeast	32	3.1–5.0	100	36–160	83.2	—	—	[120]
Sugar beet juice	200	Batch	Immobilization of cells on loofa sponge	S. cerevisiae, Candida brassicae, and Z. mobilis	30	6.5	200	—	—	0.08–0.53	72.4–86.1	[3]