Streptomyces clavuligerus is a species of Gram-positive bacterium notable for producing clavulanic acid.[1] S. clavuligerus ATCC 27064 (NRRL 3585, DSM 738) was first described by Higgens and Kastner, who isolated it from a South American soil sample.[2] Its name refers to the shape of its spore-bearing hyphal branches: from the Latin, clavula, meaning little club, and igerus, meaning bearing. S. clavuligerus spores are gray to grayish-green.[2] S. clavuligerus produces over 20 secondary metabolites, including many beta-lactam antibiotics such as clavulanic acid, cephamycin C, deacetoxycephalosporin C, penicillin N (an intermediate in cephamycin C pathway), and at least four other clavams.[3][4] Non-β-lactam antibiotics include holomycin and an antibiotic complex, MM 19290, related to tunicamycin;[5] a beta-lactamase-inhibitory protein (BLIP) has also been described.[6] Another important characteristic of S. clavuligerus is that it is not able to use glucose as a carbon source because it lacks a glucose transport system.[7][8] It also possesses all the enzymes of the urea cycle, which is unusual for a prokaryote, although it is not clear whether the urea cycle is functional.[9] Alvarez-Alvarez, R.; Rodriguez-Garcia, A.; Santamarta, I.; Perez-Redondo, R.; Prieto-Dominguez, A.; Martinez-Burgo, Y.; Liras, Paloma (May 2014). "Transcriptomic analysis of Streptomyces clavuligerus Delta ccaR:: tsr: effects of the cephamycin C-clavulanic acid cluster regulator CcaR on global regulation". Microbial Biotechnology 7 (3): 221-231. doi:10.1111/1751-7915.12109. Retrieved 8 November 2014.