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Synthesis of the industrial mechanical pretreatment used in wet anaerobic digestion according to the type of feedstock
Source publication
Although drawing inspiration from live animals to develop processes, technologies, or materials is not a new approach, there is rising interest toward biomimicry for implementing new ideas. This review presents the mechanisms and strategies of mechanical pretreatment developed by animals to enhance the digestion of their food. There is ample data i...
Citations
... Mechanical pretreatments reduce the size of LCB particles and increase the relative surface area, which leads to considerable increases in methane production. Although cutting and crushing techniques are not the most commonly used by animals, they are the ones often applied as mechanical pretreatment of biomasses during anaerobic digestion [31]. A basic mechanical pretreatment is an intrinsic part of the substrate handling for effective feeding and also a prerequisite in stirred tank reactors to prevent mechanical failures. ...
In order to partially mimic the efficient lignocellulose pretreatment process performed naturally in the gut system of Pachnoda marginata larvae, two wheat straw pretreatments were evaluated: a mechanical pretreatment via cutting the straw into two different sizes and an alkaline pretreatment with calcium hydroxide. After pretreatment, gut enrichment cultures on wheat straw at alkaline pH were inoculated and kept at mesophilic conditions over 45 days. The methanogenic community was composed mainly of the Methanomicrobiaceae and Methanosarcinaceae families. The combined pretreatment, size reduction and alkaline pretreatment, was the best condition for methane production. The positive effect of the straw pretreatment was higher in the midgut cultures, increasing the methane production by 192%, while for hindgut cultures the methane production increased only by 149% when compared to non-pretreated straw. Scanning electron microscopy (SEM) showed that the alkaline pretreatment modified the surface of the wheat straw fibers, which promoted biofilm formation and microbial growth. The enrichment cultures derived from larva gut microbiome were able to degrade larger 1 mm alkaline treated and smaller 250 µm but non-pretreated straw at the same efficiency. The combination of mechanical and alkaline pretreatments resulted in increased, yet not superimposed, methane yield.
