As discussed in the sections above, the biochemical route seems to have better attrib­utes such as low cost and easy operation and can be operated in a smaller scale in the vicinity of feedstock production facilities. However, the major hurdle to the imple­mentation of the biochemical route in commercial scale is the pretreatment of the feedstock to produce sugars. In addition to pretreatment issue, fermentation of the pretreated hydrolyzate also remains a great challenge. The key objective of the lig — nocellulosic fermentation should be to use all of the sugars (C5 and C6) and convert them into biofuels. This could be achieved only by genetically modified microorgan­isms having additional pathways needed to convert C5 and other sugars into biofuels.

A detailed discussion of the technical hurdles w. r.t pretreatment process is pre­sented below.