The present invention is an integral multilayered composite membrane having at least one ultrafiltration layer made by cocasting or sequentially casting a plurality of polymer solutions onto a support to form a multilayered liquid sheet and immersing the sheet into a liquid coagulation bath to effect phase separation and form a multilayered composite membrane having at least one ultrafiltration layer. Asymmetric ultrafiltration layer exposes wider pore side to feed. Separation of viruses and proteins are carried out using hydrophilic polymers.
