Enhancing biodegradability and biomethane potential of cattle paunch contents during anaerobic digestion through pre-treatment with the secretome of deep-sea Talaromyces stollii and rumen fluid

Abstract

Cattle paunch contents, the partially digested, recalcitrant solids removed from the rumen after slaughter, are a problematic slaughterhouse waste product. They are an underutilised source of low-value sustainable energy in the form of lignocellulose. To reduce their recalcitrance and increase sustainable energy recovery, this study employed biological pre-treatment strategies using the novel deep-sea cellulolytic/hemicellulolytic Talaromyces stollii SFI-F17 fungal secretome and/or rumen fluid on three lots of paunch contents. Rumen fluid treatment reduced the lignin content in each lot by 9.11 %, 17.86 % and 14.28 %. The biomethane potential (BMP) of the two-step-treated paunch contents increased by 104.68 %, 104.84 % and 83.24 %. When pre-treated with just the T. stollii SFI-F17 secretome, the BMP increased by 44.58 %, 74.47 % and 101.35 %. This study reports for the first time a biological pre-treatment of paunch contents outside the rumen, and reports a better average BMP increase during batch AD than those reported from other paunch contents pre-treatments.