Catalysis of Gas Hydrates by Biosurfactants in Seawater-Saturated Sand/Clay

Biosurfactants catalyzed natural gas hydrate formation in sand/clay packs saturated with seawater. Representative samples from the five possible biosurfactant classifications enhanced hydrate formation rate and decreased hydrate induction time. Biosurfactants increased rates 96% to 288% and decreased induction times 20% to 71% relative to the control. Micellarforming rhamnolipid reached a critical micellar concentration at 13 ppm at hydrate-forming conditions; these micelles migrated readily through a seawater-saturated sand pack to catalyze hydrate formation in another zone. The type of biosurfactant, in conjunction with specific porous media, help determine massive, dispersed, nodular, or stratified forms of hydrates. Results suggested that minimal microbial activity in ocean-floor sands can greatly influence gas hydrate formation.