The concatemerization process generates libraries of concatamers for the ELPs. Concatamers are oligomeric products of ligating a single gene with itself.  This will result in repeat segments of a gene, all of which can be transcribed and translated immediately to produce the ELP of interest.  A major problem with this synthetic route is that the number of gene repeat segments ligated together to form the concatamer cannot be controlled, leading to ELPs of different sizes, from which the ELP of a desired size must be isolated.