Alkaline pretreatments increases enzyme accessibility by degrading lignin and breaking linkage of lignin carbohydrates [ 4], in which ammonia pretreatment is widely applied due to the recoverability of ammonia.
Crystallinity of cellulose as well as branches of xylan also influence enzymatic saccharification [ 7, 8], and lignification strongly reduces cellulose accessibility to degrading enzymes [ 9].
Furthermore, the pretreatment process increases the biomass porosity and consequently accessibility of degrading enzymes or bacteria to the inside of the biomass.
Ultrasound treatment leads to formation of small cavitation bubbles which rupture the cellulose and hemicellulose fractions thereby increasing the accessibility to cellulose degrading enzymes for effective breakdown into simpler reducing sugars.
The higher degradation rate of the foams may result from the greater accessibility of the material for degrading cells, including osteoclasts, and blood vessels.
The increase in glucan accessibility to cell wall degrading enzymes could help contribute to reducing the energy and environmental impacts of the lignocellulosic bioethanol production process.
The reduction in interpolymeric cross-linking such as those mediated via diferulic acid would be expected to affect the ease of extraction of arabinoxylans and enhance the accessibility of cell wall degrading cellulases during saccharification.
Pectins, especially in dicots, compose 35% of primary plant cell walls and up to 5% of walls in wood tissue [ 27] and are critical for tissue integrity and accessibility to cell wall-degrading enzymes (CWDEs).
A cell wall component that, particularly in dicots, is critical for tissue integrity and accessibility to cell wall-degrading enzymes (CWDEs) is the cohesive pectin matrix embedding the cellulose-hemicellulose network that confers rigidity to the cell wall [ 4].
According to the accepted threshold for node degradation (around 99%), the real accessibility in the second case study, before the upgrade is performed, indicates that the node is consistently degraded after the eighth hour.
The idea that cytoplasmic compartmentation of transcripts plays a role in accessibility to the degradative machinery could also provide an attractive explanation for why viral mRNAs are not degraded during lytic replication.
