Investigation of alkaline pretreatment parameters on amulti-product basis for the co-production of glucose and hemicellulose based films from corn cobs

Toraman, Hilal Ezgi
There is an increasing trend in the world for using renewable sources of fuels and chemicals due to the continuous depletion of fossil fuel reserves besides the environmental issues related with the exploitation of these resources. Lignocellulosic biomass is seen as the most promising candidate to be used instead of fossil sources because of its availability, relatively low price and less competition with food and feed crops. In this study, corn cobs, a lignocellulosic agricultural waste, were subjected to alkaline pretreatment for the co-production of glucose and hemicellulose based films with a multi-product approach in order to diversify the product range and to increase the revenues of the process. The pretreatment applied to lignocellulosic agricultural waste has a significant impact on the quantities and properties of the products that can be produced from the lignocellulosic feedstock upon pretreatment. Within the context of this study, the parameters utilized during the alkaline pretreatment of corn cobs were investigated in terms of their effect on the amount of glucose obtained through the enzymatic v hydrolysis of the cellulosic portion and on the mechanical properties of the films obtained through the solvent casting of the hemicellulosic portion of corn cob. The pretreatment parameters including the alkaline type and concentration, addition and type of boron compound as well as the duration of pretreatment, were optimized with respect to the amounts and the properties of the products. Following the pretreatments conducted with 24 % KOH and 1% NaBH4, which were the initial pretreatment parameters in the study, a glucose yield of 22 % and a tensile energy to break of 2.1 MJ/m3 were obtained. Upon the optimization of the pretreatment procedure, the optimum pretreatment conditions were determined as 5 % NaOH, 1 % NaBH4 and 3 hours and a glucose yield of approximately 31% and a tensile energy to break of around 1.7 MJ/m3 were obtained.