biotechnological pre-treatments. Recently, the role offive ascomycete endophytic
strainsNeofusicoccum luteum, Ulocladiumsp.,Pringsheimia smilacis, Hormonema
sp. andNeofusicoccum australein lignin degradation has been studied extensively.
Application of the endophytic fungal strainHormonemasp. CECT 13092 for the
mentioned applications has been patented (Martínetal. 2014 ).
12.4.1 Effect of Fungal Pre-treatments on Enzymatic
Hydrolysis
Wood chips were inoculated with individual preinoculum of each fungal strain.
After the biotreatments and before enzymatic saccharification, a mild alkali treat-
ment was performed on solid samples, in order to improve the hydrolysis yields
(Salvachúa et al. 2011 ). An autohydrolysis (AH) pre-treatment was carried out prior
or after the fungal (and alkali) pre-treatment (Fig.12.3) (Martín-Sampedro et al.
2015b). The AH pre-treatment augmented glucose yield from 4 to 11% more than
xylose in comparison to that of untreated control (Fig.12.4). Pre-treated material
presents a major accessibility due to the decrease of hemicelluloses and the
increased porosity achieved in the biotreatment (Alvira et al. 2010 ). Earlier
enhanced sugar yields using more severe pre-treatment conditions were observed
and Martin-Sampedro et al. ( 2014 ) and Romaníet al. ( 2010 ) have been reported
glucose yields of 23–51% after AH pre-treatment with 3.1–3.8 severity factor.
When fungal pre-treatment was carried out before or after AH pre-treatment sac-
charification improved in all samples. It should be pointed out that a synergistic
effect of both pre-treatments could be observed and it was more noticeable when
Ulocladiumsp. orHormonemasp. were used: 8.5 and 8.0 times increases in total
sugar yields for both fungi (31–34% glucose and 24–29% xylose yields) regarding
no pre-treated control sample (4% glucose and 3% xylose yields) (Fig.12.4). When
the white-rot fungusTrametessp. I-62 used as a reference was inoculated after AH
pre-treatment, total sugar yields were 2–3 times higher than that of the yields
increased by autohydrolyzed E. globulus wood without fungal treatment.
Fig. 12.3 Scheme of the experimental procedure of biological pre-treatments to enhance
enzymatic saccharification. Figure extracted from Martín-Sampedro et al. (2015b)
272 Ú. Fillat et al.