Downloaded from www.microbiologyresearch.org by IP: 23.22.250.46 On: Mon, 08 Feb 2016 09:34:45 INTERNATIONAL JOURNAL OF SYSTEMATIC BACTERIOLOGY, Jan. zyxwvuts 1987, p. 69-71 Copyright zyxwvutsrqpo 0 1987, International Union of Microbiological Societies 0020-7713/87/010069-03$02.00/0 Vol. 37, No. 1 z Bacillus amyloliquefaciens sp. nov. norn. rev. F. G. PRIEST,l* M. GOODFELLOW,* L. A. SHUTE,3 AND R. C. W. BERKELEY3 Department of Brewing and Biological Sciences, Heriot Watt University, Edinburgh zyxw EHl 1 HX, United Kingdom‘; Department of Microbiology, The Medical Schoal, Newcastle upon Tyne NE2 4HH, United Kingdom2; and Department of Microbiology, The Medical School, University of Bristol, Bristol BS8 I TD, United Kingdom3 The name “Bacillus amyloliquefaciens” Fukomato 1943 was not included on the Approved Lists of Bacterial Names and has not been validly published since 1 January 1980; hence, it has lost standing in bacterial nomenclature. The taxon to which this name is applied zyxwvu is a distinct entity, and it can be distinguished from other named species of Bacillus. Consequently, the name Bacillus pmyloliquefaciens is revived for the same organism to which the name originally referred. The type strain of Bacillus amyloliquefaciens is strain ATCC 23350. The name “Bacillus amyloliquefaciens” Fukomoto 1943 (3, 4) does not appear on the Approved Lists of Bacterial Names (15) and has not been validly published since 1 January 1980; thus, it has no standing in bacterial nomencla- ture. In accordance with Rules 24a and 28a of the Interna- tional Code of Nomenclature zyxwvuts of Bacteria (6) the name is hereby revived. “Bacillus amyloliquefaciens” is responsible for much of the world production of a-amylase and protease. Its close affinity with Bacillus subtilis has long been recognized, and the organism has been given subspecies status as “B. subtilis subsp. amyloliquefuciens” (16) or has been included in B. subtilis as a variant that produces copious quantities of extracellular enzymes zyxwvuts (5). Thus, “Bacillus amylolique- faciens” is closely related to B. subtilis and the other two species which compose the B. subtilis group, Bacillus licheniformis and Bacillus pumilus. These organisms share many common properties, and few characteristics have been found by which they can be discriminated (5). Indeed, “B. amyloliquefaciens” is phenotypically so similar to B. subtilis that it is not possible to separate these organisms solely on the basis of classical tests (5,7,9,12), and it is for this reason that “B. umyloliquefaciens” was not included as a separate species on the Approved Lists (15). However, there is now a body of evidence that suggests that the name “B. amyloliquefuciens” should be revived. It has been shown that “B. amyloliquefaciens” and B . subtilis can be differen- tiated by using a number of techniques. Moreover, there is a need for this name in the enzyme industry to avoid confusion with B. subtilis, which differs metabolically and secretes different enzymes (10). Deoxyribonucleic acids (DNAs) from strains of “B. amyloliquefaciens’ zyxwvutsrq ’ have consistently been found to share less than 25, 13, and 5% homology with DNAs from strains of B. subtilis, B. licheniformis, and B. pumilus, respectively, under optimal conditions (60 to 65°C) (9, 11, 13, 17; L. A. Shute, Ph.D. thesis, University of Bristol, Bristol, United Kingdom, 1986). Although there is no universally accepted level of DNA homology which delineates a bacterial species, most workers agree that strains within a species should share at least 50 to 60% homology. Thus, although “B. amyloliquefaciens” is related to B. subtilis on the basis of molecular genetic data, the level of DNA homology is not * Corresponding author. 69 high enough for these two groups of organisms to be consid- ered a single species. In addition to the molecular genetic evidence, it has been shown that numerical analysis of phenotypic features en- ables discrimination of “B. amyloliquefaciens” from B. subtilis (9). A study of these organisms with API tests also discriminated “B. amyloliquefaciens” from B. subtilis (9); in this study eight strains of each species were examined. However, a more comprehensive study conducted later, in which 52 “B. amyloliquefaciens” strains and 131 B. subtilis strains were used (8), revealed intermediate strains which tended to obscure the distinction seen earlier (9). Neverthe- less, the species can be separated by using probabilistic identification methods based on API tests (2). All four species can also be differentiated by using pyrol- ysis gas-liquid chromatography (9) and pyrolysis mass spec- trometry (14). In previous physiological-biochemical stud- ies, Welker and Campbell (17, 18) were also able to separate B. subtilis and “B. amyloliquefaciens,” and Baptist et al. (1) were able to discriminate all four species by their enzyme electrophoresis profiles. Thus, the combined evidence suggests that “B. umylo- liquefaciens” is indeed a species separate from B. subtilis, even though it may be difficult to differentiate the two species on the basis of classical phenotypic tests alone. The data in Table 1 were derived from the studies of O’Donnell et al. (9) and Logan and Berkeley (8), in which the API system was used, and from our own unpublished data. The latter were obtaiped from a study of 17 strains of B. subtilis, 19 strains of B. pumilus, 17 strains of B. licheniformis, and 9 strains of “B. amyloliquefaciens,” including the type strain of each taxon. “B. amyloliquefaciens” strains can be distin- guished from B. subtilis strains by the inability of most strains to hydrolyze DNA and pectin, the failure of the organisms to produce acid from inulin (8), and the formation in most “B. amyloliquefaciens” strains of long chains of cells. Where these tests fail to produce a clear separation, DNA homology determinations should produce a definite identification. The description of “B. amyloliquefaciens” given below is based on the data of Welker and Campbell (17) and Gordon et al. (5) and our own unpublished data. Bacillus amyloliquefaciens sp. nov., nom. rev. Bacillus amyloliquefaciens (am. yl. 0. li. que. fac’ i. ens. Len. amylum starch; M.L. part adj. amyloliquefaciens starch digesting). Gram positive rods, 0.7 to 0.9 by 1.8 to 3.0 z pm.