Four constructs containing a Ferulic acid esterase were used to transfer and express the genes in alfalfa to modify the cell wall for increased hydrolysis potential for biofuel feed stock applications. At present, we are working on the expression of Aspergillus niger-derived ferulic esterases (FaeB) by stable transformation after co-culture with Agrobacterium containing FaeB gene constructs targeted to apoplast, chloroplast, ER and vacuole expression, followed by induction of somatic embryos.  This approach is the most rapid and efficient method developed to date. The work was performed on alfalfa genotype N4.4.2.  Plant materials derived from standard in vitro cultures of alfalfa (Medicago sativa L.) genotype N4.4.2., were propagated on 1/2MSO medium. The standard conditions for maintaining the cultures in a growth chamber were: 25^oC (day/night) with 16 hours photoperiod at about 3500 lux.  Four plates of each construct (FaeB-Apoplast, FaeB-Chloroplast, FaeB-ER, FaeB-Vacuole) were used, with 10 soaked petioles on each plate. Alfalfa transformation was performed by using Agrobacterium tumefaciens (LBA 4404) that harboured the FaeB transgene with different signalling peptides that could target FaeB proteins to four cellular compartments - Apoplast, chloroplast, ER, and vacuole. The base vector for transgene cloning  was pEACH 5103, in which tCUP4 promoter constitutively drives the expression of FaeB. The constructed vector was introduced into Agrobacterium tumefaciens by electroporation.  Molecular analysis of putative transgenic plants is underway and the segregation of transgene in progeny will be investigated.