58
biogas potential of the biomass substrate. For all these reasons, chemical pretreatment is a less popular option [73].
While the conventional physical and chemical pretreatment methods require
expensive materials and devices and imply a high energy consumption, the biological pretreatments are less energy consuming and less polluting and have low disposal costs. They involve microorganisms with cellulolytic and hemicellulolytic
abilities which contain degrading enzymes and produce the biomass biopolymer
decomposition [64]. Biological enzymatic pretreatment methods operate with mild
conditions, and even if these methods lead to a lower methane yield in anaerobic
digesters compared to the thermal methods, they have lower energy requirements
[74]. In recent years, biological pretreatment methods have become increasingly
used and common due to many advantages compared to non-biological methods,
mainly related to an enhanced total biogas and methane yield. However, the potential of these techniques is far from being sufficiently explored and exploited [75].
The effectiveness of the biological pretreatment methods is negatively affected by
the microbial growth rate which is fairly slow [76].
It is unanimously accepted that each pretreatment option has its specific advantages and disadvantages, but a cost-effective pretreatment method that should be
also environmentally friendly to completely decompose the recalcitrant compounds
from biomass for fuel gases and other value-added products is not yet decided.
Fig. 2 Pretreatment methods to enhance biomass conversion to fuel gas
C. Mateescu and A.-D. Dima
biogas potential of the biomass substrate. For all these reasons, chemical pretreatment is a less popular option [73].
While the conventional physical and chemical pretreatment methods require
expensive materials and devices and imply a high energy consumption, the biological pretreatments are less energy consuming and less polluting and have low disposal costs. They involve microorganisms with cellulolytic and hemicellulolytic
abilities which contain degrading enzymes and produce the biomass biopolymer
decomposition [64]. Biological enzymatic pretreatment methods operate with mild
conditions, and even if these methods lead to a lower methane yield in anaerobic
digesters compared to the thermal methods, they have lower energy requirements
[74]. In recent years, biological pretreatment methods have become increasingly
used and common due to many advantages compared to non-biological methods,
mainly related to an enhanced total biogas and methane yield. However, the potential of these techniques is far from being sufficiently explored and exploited [75].
The effectiveness of the biological pretreatment methods is negatively affected by
the microbial growth rate which is fairly slow [76].
It is unanimously accepted that each pretreatment option has its specific advantages and disadvantages, but a cost-effective pretreatment method that should be
also environmentally friendly to completely decompose the recalcitrant compounds
from biomass for fuel gases and other value-added products is not yet decided.
Fig. 2 Pretreatment methods to enhance biomass conversion to fuel gas
C. Mateescu and A.-D. Dima