The genomic library of Chainia in lambda gt10 was analyzed for the expression of the xylanase gene using antixylanase antibodies. The recombinants exhibiting positive enzyme-linked immunosorbent assay test showed clearance on RBB-xylan plate. The phage lysates showed xylanase activity in the range of 19 to 36 mU ml(-1), which was 20-fold higher than that exhibited by the previously cloned xylanase gene from Chainia. The pooled DNA preparation of EcoRI digests of the xylanase-positive lambda gr10 recombinants showing higher activity was cloned in pUC8. One of rite pUC8 recombinants (h(1)) which exhibited maximum activity (24 mU ml(-1)) was shown to code for the low-molecular-weight xylanase from Chainia. The xylanase produced by h(1) was inducible by isopropylthio-beta-o-galactoside (IPTG) but not by xylan, suggesting that the DNA fragment containing the xylanase gene is in frame with, and its expression controlled by, the lacZ promoter.