Interestingly, from biogas residue to conversion residue, without
the extra aid of cellulase for the biogas residue, the content
of lignin was reduced from 13.59% to 11.54% in the residue after
converted by BSFL. About 2.05% of lignin was removed in the biogas
residue and utilized for biomass accumulation of BSFL.
However, it was reported that BSFL could hardly use the lignin
component in bran for feed (Zheng et al., 2012a), but it reduced lignin
more than that ratio by adding BSFL into biogas residue in this
study. Meanwhile, there are many special bacteria with the ability
of the degradation of lignin existing in our life (Brown and Chang,
2014). So it could be hypothesized that the lignin degrading bacteria
might survive in the conversion and it needed further research
to prove.