Due to the complex composition of lichenan, lichenase alone cannot always hydrolyze it efciently. Carbohydrate-binding modules (CBMs) and lytic polysaccharide monooxygenases (LPMOs) have been confrmed to increase the hydrolysis efciency of lichenases. However, their practical application was hampered by the complex and costly preparation procedure, as well as the poor stability of LPMOs. Herein, we discovered a novel and stable auxiliary protein named SCE to boost the hydrolysis efciency. SCE was composed of SpyCatcher (SC) and elastin-like polypeptides (ELPs) and could be easily and cheaply prepared. Under the optimal conditions, the boosting degree for SCE/lichenase was 1.45, and the reducing sugar yield improved by nearly 45%. The results of high-performance liquid chromatography (HPLC) indicated that SCE had no infuence on the hydrolysis pattern of lichenase. Through the experimental verifcation and bioinformatics analysis, we proposed the role of SCE in promoting the interaction between the lichenase and substrates. These fndings endow SC with a novel function in binding to insoluble lichenan, paving the way for biomass degradation and biorefnery. Key points: • A novel self-purifcation auxiliary protein that could boost the hydrolysis efciency of lichenase has been identifed. • The protein is highly produced, simple to prepare, well stable, and does not require any external electron donor. • The novel function of SpyCatcher in binding to insoluble lichenan was frst demonstrated. Keywords: Lichenase · SpyCatcher · Boosting efect · Biomass degradation.