Protaetia brevitarsis larvae can feed on and convert spent mushroom substrate from Auricularia auricula and Lentinula edodes cultivation

•Protaetia brevitarsis larvae effectively converted spent mushroom substrate from Auricularia auricula (SMS-AA) and Lentinula edodes (SMS-LE).•The larvae produced nutrient-enriched organic fertilizer with a phytotoxicity-free.•The larvae were able to efficiently digest and thus utilize lignocellulose.•We present a new strategy for the use of woodchip-derived spent mushroom substrates. The edible mushroom industry produces massive amounts of spent mushroom substrate (SMS). Thus, there is an urgent need for high-value utilization technology to process the SMS, especially SMSs originating from woodchips. Protaetia brevitarsis larvae (PBL) can feed on various types of organic matter and can produce organic fertilizer and insect protein. In this study, we investigated the potential of PBL to utilize and convert SMSs from Auricularia auricula (SMS-AA) and Lentinula edodes (SMS-LE) cultivation. The results showed that the PBL were able to feed on SMS-AA and SMS-LE and form nutrient-enriched organic fertilizer with a low phytotoxicity and high humic acid content. Further analysis of the organic carbon dynamics suggested that PBL can efficiently digest and utilize lignin. This study demonstrates a new strategy for the utilization of SMSs originating from woodchips, and provides a new model for further investigations on the mechanism of lignin decomposition.