concentrating protein by method other than tff - (Aug/23/2010 )

Our protein is produced as IBs and we perform solubilization and refolding of the protein. this is then concentrated by proflux system and then loaded to ion exchange column. Our refolding buffer volume is 10-20L and our columns are 100 ml so we cannot directly load 10-20 L volume on them. the problem is on concentrating, our protein aggregates and we get low yield. Is there any other method to concentrate the protein prior to loading to ion exchange.

regards

Can you precip the protein?