Abstract: The present application is directed to the preparation of low viscosity bio-oils from the hydrothermal liquefaction (HTL) of lignocellulosic biomass in the presence of a crude glycerol and water mixture achieving a high biomass conversion ratio. The modified HTL process allows the direct use of crude glycerol as an effective solvent for biomass liquefaction creating a highly efficient and cost-effective process. Furthermore, the resulting bio-oils containing liquefied biomass, crude glycerol and water, were successfully applied as an inexpensive green substitute in the preparation of bio-based phenol formaldehyde (BPF) adhesives which retain bonding strengths (dry or wet strength) as required by ASTM standard and free formaldehyde emission levels at the F*** and F**** level according to the JIS standard.