Abstract: The present invention relates to a sack for liquid or pulverulent materials having an areal section (F) composed of a water-soluble polymer, wherein dissolution of the water-soluble polymer gives rise to an opening through which the sack can be emptied, to a sack according to the invention that contains a liquid or pulverulent material, to a method for the emptying thereof and the production thereof, and also to the use of the sack for the packing of liquid or pulverulent materials and to the use of an areal section (F) composed of a water-soluble polymer as part of a sack for liquid or pulverulent materials for the reduction of the release of unpleasant odors and/or harmful substances into the air, especially for the reduction of the release of alveoli-reaching dusts.

Abstract: The present invention relates to a novel biopolymer consisting of a three-dimensional cross-linked mixture of (a) a cross-linking agent, activated with an activating agent, dissolved in a aqueous solution, and (b) a recombinant protein, namely polyubiquitin. The novel biopolymer is based on the cross-linking of ubiquitin (monomeric and/or polymeric) with a cross-linking agent, preferably bifunctionalized polyethylene oxides or a polyethylene glycol of various molecular masses (MW 2000 to 35 000 kDa), dissolved in aqueous solution in adequate proportions. The novel biopolymer offers a wide range of formulations since the number of ubiquitin units and cross-linking agent can vary both in length and ratio. The novel hydrogel is also biodegradable by a specific protease and is resistant to a wide range of other proteases.