The objective of this study was to develop a solution for promoting egl3 gene of Trichoderma reesei (coding beta-1,4-endoglucanase, EGIII) high-efficiency secretory expression in Escherichia coli and Lactococcus lactis and to investigate the effect of the best recombinant on degrading paper and wheat straw. The coding sequence of the egl3 gene fused with a gene fragment of Usp45 (usp45) of L. lactis was cloned to pMG36e and was expressed in E. coli DH 5 alpha (DH 5 alpha) and L. lactis subsp. lactis MG1363 (MG1363). The maximal productivity in recombinant DH 5 alpha was 226 mU mL(-1) for extracellular EGIII and 535 mU mL(-1) for intracellular EGIII. The maximal productivity in recombinant MG1363 was 1118 mU mL(-1) for extracellular EGIII and 761 mU mL(-1) for intracellular EGIII. The plasmid stability in recombinant MG1363 was higher than 85% at 60 generations. Recombinant MG1363 vigorously degraded paper and wheat straw and produced sufficient acids. This study provided EGIII transgenic lactic acid bacteria for processing agricultural byproducts.