Degradation of spent casings with commercial cellulases

Spent casings (SC) are a coproduct of the frankfurter/sausage processing industries; traditional disposal methods (landfills and land application) are becoming costly or limited. Reusing SC as food for animals could provide a disposal alternative. The objective was to determine if ruminal bacteria or commercial cellulases could degrade SC. The cellulases of ruminal bacteria were unable to degrade SC. One cellulase (C3) was very effective in degrading cellulosic substrates; it degraded SC approximately 95% by 6 h and 98% by 12 h into glucose, but the glucose concentration was low (about 2.5 mM). Activity of C3 was greatest at a pH of 4.0 and a temperature of 56–60°C; particle size and pigmentation of SC did not affect degradation. Spent casings could be reused as animal feed, but a bioprocessing approach is needed to increase glucose concentration and remove water before this would be feasible