The crystalline and indigestible form of cellulose, the most abundant biomass material on earth, can now be broken down into a gelatinous and amorphous form using pressurized superheated hot water. This novel form of cellulose becomes open to enzymic action and so could be a useful new feedstock for a wide range of products. Shigeru Deguchi of the Japan Agency for Marine-Earth Science and Technology and colleagues at Hokkaido University reasoned that the fact that the common polysaccharide starch can be gelatinized at 60-70 Celsius might suggest that cellulose could be converted similarly under more extreme conditions. They were successful at 320 Celsius and 25 MPa, by following loss of birefringence using polarized optical microscopy. As with starch, the gelatinization process was not reversible.