Effects of enzymatic hydrolysis and ultrasounds pretreatments on corn cob and vine trimming shoots for biogas production

•The enzymatic hydrolysis enhanced the transformation of VTS and corn cob into biogas.•The ultrasounds pretreatment harmed the biogas generation from both materials.•The US + H pretreatment improved the biogas production from corn cob but not from VTS.•The impact of pretreatments for biogas generation was more noticeable for VTS.

Due to their lignocellulosic nature, corn cob and vine trimming shoots (VTS) could be valorized by anaerobic digestion for biogas production. To enhance the digestibility of substrates, pretreatments of lignocellulosic materials are recommended. The effect of enzymatic hydrolysis, ultrasounds pretreatments (US) and the combination of both was assayed in lignocellulosic composition, methane, and biogas yields. The pretreatments leaded to a reduction in lignin and an increase in neutral detergent soluble compounds making corn cob and VTS more amendable for biogas conversion. The US were negative for biogas production from both substrates and in particular strongly detrimental for VTS. On the opposite side, the enzymatic hydrolysis was certainly beneficial increasing 59.8% and 14.6% the methane production from VTS and corn cob, respectively. The prior application of US did not potentiate (or not sufficiently) the improvement in the methane production reflected by the enzymatic hydrolysis pretreatment of VTS and corn cob.