Evaluation of possibility to produce green biocellulose nanofibers in simultaneous saccharification and fermentation of sustainable agro-industrial residues

摘要

The present study evaluates possibility to produce biocellulose nanofibers (BC) in simultaneous saccharification and fermentation (SSF). Pre-treated wheat straws (WS) were further incubated in the fermentation broth in the presence of Gluconacetobacter xylinus bacterium in the presence and absence of hydrolysis enzymes. WS were not filtered as common during separate hydrolysis and fermentation (SHF). Generally, results in the present study demonstrate that. BC production in SSF is rather challenging, especially in the presence of hydrolysis enzymes. Total sugars produced during SSF were higher than SHF, and were generally identical under different pre-treatment and hydrolysis conditions (~54 g/L). This represents maximum amounts at complete hydrolysis of biomass due to the longer incubation time compared to SHF. Maximum BC production of 10.8 g/L was achieved when WS was chemically pretreated with 1% (by volume) dilute acid for 30 minutes at 121°C. Sample pre-treated with 2% acid at similar conditions resulted in 8.93 g/L BC produced. Typically, increasing duration and temperature of thermal treatment produced slightly more sugars, however, resulted in inhibited bacterial cells growth and resulted in slightly lower BC production. Considering that BC is also a good substrate for the cellulose, explains the higher concentration of remaining sugars (i.e., 15.50 g/L) when enzymatic hydrolysis was used. This led to lower yield of the final BC produced.