A cost competitive biomaterial for widespread applications in food and water technology is an urgent need. We report a new hydrophobic biomaterial film for soluble pollutant sorption and reduction of microbial load in water environment. Guar gum from the seeds of Cyamopsis tetragonolobus was hydrophobically modified following benzoyl chloride reaction in aqueous alkali. The new biopolymer derivative is insoluble in water and form castable films with a high degree of surface hydrophobicity. The film water vapor permeability was 0.233 +/- 0.029 g mm kPa(-1) h(-1) m(-2) and the tensile property was 38.65 +/- 3.66 MPa. The film surface contact angle against water was 77.36 +/- 1.09 degrees. The new biomaterial film demonstrated strong antimicrobial contact killing against both gram positive and gram negative bacteria. It also act as an efficient sorbent for a range of water soluble organic pollutants. (C) 2012 Elsevier Ltd. All rights reserved.