Alternative Low-Cost Additives to Improve the Saccharification of Lignocellulosic Biomass
A potential strategy to mitigate problems related to unproductive adsorption of enzymes onto lignin during the saccharification of lignocellulosic biomass is the addition of lignin-blocking agents to the hydrolysis reaction medium. However, there is a clear need to find more cost-effective additives for use in large-scale processes. Here, selected alternative low-cost additives were evaluated in the saccharification of steam-exploded sugarcane bagasse using a commercial enzymatic cocktail. The addition of soybean protein, tryptone, peptone, and maize zein had positive effects on glucose release during the hydrolysis, with gains of up to 36% when 8% (w/w) soybean protein was used. These improvements were superior to those obtained using bovine serum albumin (BSA), a much more expensive protein that has been widely reported for such an application. Moreover, addition of soybean protein led to a saving of 48 h in the hydrolysis, corresponding to a 66% decrease in the reactor operation time required. In order to achieve the same hydrolysis yield without the soybean additive, the enzyme loading would need to be increased by 50%. FTIR spectroscopy and nitrogen elemental analysis revealed that the additives probably acted to reduce unproductive binding of cellulolytic enzymes onto the lignin portion of the sugarcane bagasse.
KeywordsAdditives Sugarcane bagasse Adsorption Lignin Lignocellulosic biomass Enzymatic hydrolysis
The authors would like to thank Embrapa, CNPq (Process 401182/2014-2), CAPES, and FAPESP (Processes 2014/19000-3, 2016/10636-8, and 2017/13931-3) (all from Brazil) for financial support.
Compliance with Ethical Standards
The authors declare they have no competing interests.
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