NOVELTY - Concentrating microorganisms in an aqueous solution, involves contacting the solution with the water-insoluble matrix having polymer capable of binding microorganism, the polymer comprises several residues, which comprise several amino acid residues and hydrophobic moiety residues, where the hydrophobic moiety residues are linked to amino acid residues through an amine group of one amino acid residue and through carboxyl of the other amino acid residue in amino acid residues, and the polymer being chosen from linear and cyclic polymer.    USE - The method is useful for concentrating microorganisms in an aqueous solution chosen from potable water, reservoir water, natural source water, swimming pool water, hot-tub water, fountain water, sewage, wastewater, spent water, irrigation water, liquid consumer product, liquid food product, biological or biochemical assay solution, bodily fluid, blood sample, culture medium, urine sample, spinal fluid sample, saliva sample, tears and an amniotic fluid sample (all claimed), where the microorganism are chosen from prokaryotic organisms (e.g. acidobacteria and actinobacteria), eubacterium, proteobacterium (e.g. Burkholderiales (Bordetella)), archaebacterium (e.g. crenarchaeota and euryarchaeota), eukaryotic organisms, yeast, fungi, algae, protists, protozoan, and other parasites.    ADVANTAGE - The method enables efficient concentration, detection, quantification and identification of pathogens in large volumes of liquid samples, and specificity binds towards microbial species which allows separating and concentrating bacteria from other contaminants with similar sizes.    DETAILED DESCRIPTION - Concentrating (M1) microorganisms in an aqueous solution, involves contacting the solution with a water-insoluble matrix having a polymer capable of binding the microorganism covalently attached to it, the polymer comprises several residues, in which several residues comprise several amino acid residues and two or more hydrophobic moiety residues, where the hydrophobic moiety residues is covalently linked to amino acid residues in the amino acid residues through an amine group of one amino acid residue and through carboxyl of the other amino acid residue in amino acid residues, the polymer being chosen from linear polymer and a cyclic polymer, thus binding the microorganisms to the polymer on the matrix. INDEPENDENT CLAIMS are included for the following:    (1) method of depleting microorganisms from an aqueous solution, involves performing the steps in the above-sited method (M1), and collecting the solution depleted from the microorganisms;    (2) device for concentrating microorganisms, comprises one or more casing and a water-insoluble matrix, and the water insoluble matrix, where the matrix is configured to allow an aqueous solution which comprises the microorganism to flow through, thus binding the microorganisms to the polymer on the matrix;    (3) detecting and identifying microorganisms in an aqueous solution, involves performing the steps provided in the above-sited method (M1), and identifying the microorganism bound to the matrix;    (4) a sterile composition comprises water-insoluble matrix having a polymer capable of binding the microorganism covalently attached to it, the polymer comprises several residues, where several residues comprise several amino acid residues and at least two hydrophobic moiety residues, where the hydrophobic moiety residues is covalently linked to amino acid residues in several amino acid residues through an amine group of one amino acid residue and through a carboxyl of the other amino acid residue in the amino acid residues, the polymer is chosen from a linear polymer and cyclic polymer; and    (5) composition comprises a water-insoluble matrix having a polymer capable of binding the microorganism covalently attached to it, the polymer comprises several residues, where several residues comprise several amino acid residues and at least two hydrophobic moiety residues, where at least one of the hydrophobic moiety residues is being covalently linked to at least two amino acid residues in several amino acid residues through an amine group of one amino acid residue and through a carboxyl of the other amino acid residue in the at least two amino acid residues, the polymer is chosen from linear polymer and cyclic polymer, and microorganisms bound to the polymer.