Ethanol fermentation of sugarcane molasses by Zymomonas mobilis MTCC 92 immobilized in Luffa cylindrica L. sponge discs and Ca-alginate matrices

Abstract

Bio-ethanol production from cane molasses (diluted to 15 % sugar w/v) was studied using the bacterium, Zymomonas mobilis MTCC 92 entrapped in luffa (Luffa cylindrica L.) sponge discs and Ca-alginate gel beads as the immobilizing matrices. At the end of 96 h fermentation, the final ethanol concentrations were 58.7 ± 0.09 and 59.1 ± 0.08 g/l molasses with luffa and Ca-alginate entrapped Z. mobilis cells, respectively exhibiting 83.25 ± 0.03 and 84.6 ± 0.02 % sugar conversion. There was no statistical significant difference (Fischer's LSD) in sugar utilization (t = 0.254, p<0.801) and ethanol production (t =-0. 663, p<0.513) between the two immobilization matrices used. Further, the immobilized cells in both the matrices were physiologically active for three more cycles of operation with less than 15 % decrease in ethanol yield in the 4 th cycle, which was due to some leakage of cells. In conclusion, luffa sponge was found to be equally good as Ca-alginate as a carrier material for bacterial (Z. mobilis) cell immobilization for ethanol production.Further, it has added advantages such as it is cheap, non-corrosive and has no environmental hazard.

Immobilization and association of microorganisms to improve fermentation performance for ethanol production

“…The literature reports higher yields (Behera et al, 2012), but in this experiment, this was not observed. These ethanol concentrations represented 78 and 76% of theoretical yield, respectively (Figure 1).…”

<b>Ethanol and Levan production by sequential bath using <i>Zymomonas mobilis</i> immobilized on alginate and chitosan beads

“…However, no variable presented significant statistical interference (p < 0.05) ( Table 6). Ethanol production efficiency using Z. mobilis immobilized on alginate beads was also reported by Yamashita, Kurosumi, Sasaki, and Nakamura (2008); Behera et al (2010) and Behera, Mohanty, and Ray (2012). Chitosan support gave maximum ethanol production of 5.24 g L , both in trial 9, and the variables sucrose, fermentation time and agitation presented significant statistical interference (Table 6 and Figure 2).…”

“…Zymomonas mobilis is highlighted in the literature as a promising microorganism for ethanol and other products of technological interest production such as the gum levan (or fructan) mainly due to its capacity to tolerate high ethanol and sugar concentrations, produce low biomass concentration, use the Entner-Doudoroff metabolic pathway for carbohydrate metabolism and show cell growth regardless of carbon consumption (Behera, Mohanty, & Ray, 2012;Pentjuss, Kostromins, Fell, Stalidzans, & Kalnenieks, 2013).…”

Zymomonas mobilis IMMOBILIZED ON LOOFA SPONGE AND SUGARCANE BAGASSE FOR LEVAN AND ETHANOL PRODUCTION USING REPEATED BATCH FERMENTATION

“…On a worldwide scale, the ethanol production is concentrated in Brazil and the USA and uses edible raw materials, mainly sugarcane and corn, which is of concern in relation to food scarcity, due to the need to increase environmental exploration. Given this reality, intense research has been carried out throughout the world with a view to developing viable alternatives to increase the efficiency of ethanol production (Watanabe et al, 2012;Behera et al, 2012).…”

“…Different techniques and supports for cell immobilization can be found in the literature, and the use of lignocellulosic supports such as loofa sponge and sugarcane bagasse has been widely cited (Chandel et al, 2009;Behera et al, 2012). These supports are used for immobilization by adsorption and are efficient due to presenting good stability to different chemical and physical treatments and having an extensive surface for cell adhesion.…”