References

259

The factual bioethanol conversion efficiency was 86.8% [39]. Mahboubi et al. made

to remediate some issues associated with hydrolysis and fermentation, by inte-

grating immersed membrane bioreactors (iMBRs) into lignocellulosic bioethanol

production process. In this regard, double-staged continuous saccharification

filtration and co-fermentation filtration of wheat straw slurry were conducted using

iMBRs at filtration fluxes up to 51 l/m² h (liter per meter square hour [LMH]) [40].

Process effectiveness for the second-generation ethanol production depends

mostly on the type of lignocellulosic raw material. Thus, the optimization for each

step concerned in olive tree pruning biomass valorization was studied: (i) alkaline

pretreatment of the original feedstock, (ii) diluted acid hydrolysis of pretreated

solids, and (iii) fermentation of the hemicellulosic hydrolyzates for ethanol produc-

tion by Scheffersomyces stipitis. The recommended alkaline pretreatment conditions

were 30 minutes, 90 ^∘C, and 0.5% w/v NaOH, with losses of 88.3% of acetyl groups

from starting biomass, but only 6.9% of D-xylose. A significant improvement in

ethanol production was observed in treated hemicellulose liquor (20.4 g/dm³,

Y P/S = 0.20 g/g, and QP = 0.21 g/dm³ h) [41].

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