Detoxification of furanic and phenolic lignocellulose derived inhibitors of yeast using laccase immobilized on bacterial cellulosic nanofibers

Publication date: Available online 9 November 2016 Source:Journal of Molecular Catalysis B: Enzymatic Author(s): Thiyagarajan Saravanakumar, Han-Sung Park, Ae-Young Mo, Myoung-Suk Choi, Dae-Hyuk Kim, Seung-Moon Park Biotransformation of lignocellulose by microbial fermentation is usually preceded by thermo-chemical pretreatments followed by enzymatic hydrolysis of cellulose. Derivatives formed during the pretreatment of the lignocellulosic biomass inhibit enzymatic hydrolysis as well as microbial fermentation. Pretreated lignocellulose hydrolysate contains many derivatives of either furanic or phenolic inhibitory derivatives. In the present study, laccase was used to detoxify three different types of lignocellulosic derivatives that are highly toxic to microbial fermentation due to their low hydrophilic nature, namely furfural, acetosyringone, and coniferyl aldehyde. A minimal inhibitory concentration (MIC) test was carried out with Saccharomyces cerevisiae. The MIC of furfural, acetosyringone, and coniferyl aldehyde was 12mM, 24mM, and 1.5mM, respectively. Laccase was immobilized on to cellulose nanofiber produced by Gluconacetobacter xylinus. Immobilized laccase showed a better pH and thermal stability than free laccase. Reuse of immobilized laccase retains 85% of its enzyme activity after 16 recycles. Immobilized laccase completely degraded the three lignocellulose inhibitory derivatives after 36h of incubation at 40°C. Finally, the degradation was confirmed by ul...
Source: Journal of Molecular Catalysis B: Enzymatic - Category: Biochemistry Source Type: research