Ethanol production from cotton gin trash using optimised dilute acid pretreatment and whole slurry fermentation processes

Production of cellulosic ethanol from cotton processing residues after pretreatment with dilute sodium hydroxide and enzymatic hydrolysis

“…The ethanol yield in 12 h was 85.5 ± 1.7% for the glucose control, 86.9 ± 1.6% for CGD hydrolysate and 87.5 ± 0.7% for CGW hydrolysate with ethanol volumetric productivities of 1.5 ± 0.1, 1.6 ± 0.1 and 1.7 ± 0.1 g L À1 h À1 , respectively. These data are consistent with those of McIntosh et al (2014), who also tested the ethanol fermentation of CGW hydrolysates using the same S. cerevisiae Thermosacc Dry industrial strain. The fermentations were completed within 9 h, yielding 85% of the ethanol theoretical yield (16 g L À1 ) with an overall maximum ethanol volumetric productivity of 2.3 g L À1 h À1 .…”

“…These variations in glucan could be attributed to the ginning methods, since some gins had higher cotton lint content than others and may contain variable amounts of hulls (16-48%), seeds (6-24%), motes (16-24%), and leaves (14-30%). McIntosh et al (2014) also found low cellulose quantities (24-36%) and high levels of extractives (26-28%) in three types of cotton gin residues.…”

“…The high total world production capacity of cotton fibers also equates to the production of high amounts of cotton gin residues (McIntosh et al, 2014). In Brazil, 900 thousand hectares are destined to cotton production (USDA, 2014).…”

“…The major advantage of these cotton residues compared to other lignocellulosic materials is their high cellulose content. Hence, these renewable feedstocks have been tentatively used in a number of bioenergy applications to avoid its disposal by incineration or landfilling, such as in the case of cellulosic ethanol (Agblevor et al, 2003;McIntosh et al, 2014), pyrolysis (Zabaniotou et al, 2000), gasification (Sadaka, 2013), anaerobic fermentation (Isci and Demirer, 2007) and catalytic conversion to value-added chemicals (Grilc et al, 2015). However, the supporting evidence for the application of cotton gin residues for ethanol production is relatively scarce in comparison to other notable agricultural residues such as corn stover, sugarcane bagasse and wheat straw (McIntosh et al, 2014).…”

Effect of Various Pretreatment Methods on Bioethanol Production from Cotton Stalks

“…The length of pre-hydrolysis step was set at 6 h while an enzyme load of 80 FPU/g cellulose was used [20]. In general, 7 to 33 FPU/g substrate are used for cellulose hydrolysis in lignocellulosic material, but in some cases higher enzyme loadings are necessary to efficiently hydrolyze the substrate [27,33]. Glucose release during pre-hydrolysis step was found to be dependent on the pretreatment applied and ranged from 18.77 g/L (corresponding to a hydrolysis yield of 23.81%) for hydrothermally treated CS (Figure 1a) to 35.81 g/L (corresponding to a hydrolysis yield of 27.00 %) for organosolv-hydrothemally treated CS (Figure 1b).…”