EFFECT OF SURFACTANTS AND ZEOLITES ON SIMULTANEOUS SACCHARIFICATION AND FERMENTATION OF STEAM-EXPLODED POPLAR BIOMASS TO ETHANOL

In this work, the effect of the addition of different concentrations o f Tween-80 and three different zeolite-like products on enzymatic hydr olysis, ethanol fermentation, and simultaneous saccharification and fe rmentation (SSF) process has been investigated. The ability of these p roducts to enhance the effectiveness of the SSF process to ethanol of steam-exploded poplar biomass using the thermotolerant strain Kluyvero myces marxianus EMS-26 has been tested. Tween-80 (0.4 g/L) increased e nzymatic hydrolysis yield by 20% when compared to results obtained in hydrolysis in absence of the additive. Zeolite-like products (ZESEP-56 and ZECER-56) (2.5 g/L) improved rates of conversion and ethanol yiel ds in the fermentation of liquid fraction recovered from steam-explode d poplar. The periods required for the completion of fermentation were approx 10 h in the presence of zeolite-like products and 24 h in the absence of additives. The probable mode of action is through lowered l evels of inhibitory substances because of adsorption by the additive.