IMPROVEMENT OF BIOETHANOL PRODUCTION BY USING Saccharomyces cerevisiae [Meyen ex E.C. Hansen] IMMOBILIZED ON PRETREATED SUGARCANE BAGASSE

Abstract

Pretreated of sugarcane bagasse was used as a carrier for immobilization of Saccharomyces cerevisiae. Pretreatments were carried out by steaming, pressurized steam, and combination both of procedure. The objectives of this research was to investigate the effect of pretreatment on sugarcane bagasse to cells adsorption and bioethanol production. Immobilization process was conducted in a ratio of 2.5 g carrier/50 mL cell suspension. Whole cell biocatalyst as much as 1% (w/v) was used as inoculum for bioethanol fermentation. The best pretreated sugarcane bagasse for carrier of immobilized cells was obtained using steam treatment for 30 minutes. Those treatment improved the physical properties of carrier and increased the cell retention up to 10.05 mg/g. The use of whole cell biocatalyst after steaming pretreatment also enhanced ethanol yield 1.5 times higher than control.

Supporting role of lignin in immobilization of yeast on sugarcane bagasse for continuous pectinase production

“…The results obtained in this study were also corroborated by the SEM data which demonstrated bunching of yeast cells on the surface of untreated SB fibers (Fig. 4(a)) where cells were immobilized more effectively 10 . After the immobilization process, cells attached through the pores and formed colonies.…”

“…Pretreatment resulted in lignin removal which ultimately made the structure of SB fragile 15 and hence cell retention decreased significantly on pretreated SB. In an earlier work, SB was prepared for immobilization by steam pretreatment 10 . However, the requirement of high temperature and compatible reactors limit the application of steam treatment.…”

“…Figures 4(b) and (c) also reveal the damaged surface of pretreated SB and fewer yeast cells in both the pretreated matrices. Furthermore, immobilization of yeast to pretreated SB might have an effect on intrinsic cell growth rate 10 that could have decreased the cell retention. Nonetheless, the results for all the parameters revealed the potential of UTB as an immobilization matrix for G. candidum AA15 as compared to pretreated SB.…”

“…Lignin in SB has to be removed when SB is used as substrate for microorganisms and their enzymes, because it seals the fermentable and hydrolysable components, cellulose and hemicelluloses 9 . However, lignin gives stability and rigidity to the substrate 10 . Such features are desirable for immobilization matrices, and therefore it was hypothesized that any such pretreatment to de‐lignify SB would adversely affect immobilization and subsequent industrial processes.…”