ZoBell — 144 — Marine Microbiology 



chitinoclastic bacteria which commonly occur in great numbers in the ali- 

 mentary tracts of such animals. One of the best sources of chitinoclastic 

 bacteria is the stomach contents of squid and other cephalopods which 

 ingest chitinous food. Hock (1940) recovered chitinoclastic bacteria from 

 the intestinal contents of seven different genera of marine animals. 



Benecke (1905) isolated Bacillus chitinovorus from the polluted water 

 of Kiel harbor. It is doubtful if this organism, which digests chitin, is a 

 true marine species since it has been found in soil and it grows well in 

 fresh-water media. 



Waksman et al. (1933c), Bertel (1935), and ZoBell and Anderson 

 (1936&) have found chitinoclastic bacteria to be widely distributed in 

 marine bottom deposits. From the lesions of live lobsters having a shell 

 disease, Hess (1937) isolated a number of strains of chitinoclastic bac- 

 teria. Johnson (1932) found chitinoclastic bacteria growing on crabs 

 packed in ice. From the shells of crabs in an advanced stage of decom- 

 position, she isolated several kinds of chitin-destroying bacteria. 



After finding chitinoclastic bacteria in 8 out of 27 samples of solar 

 salt obtained from Africa, Spain, South America, California, and the West 

 Indies, Stuart (1936) concluded that such bacteria are probably widely 

 distributed in the sea. Most of the bacteria were Gram-negative aerobes, 

 morphologically resembling S err alia and Sarcina. Stuart expressed the 

 belief that halophilic chitinovors or chitinoclasts may be responsible for 

 damage to skins and hides. 



Between o.i and i.o per cent of the marine mud-dwelling bacteria 

 studied by ZoBell and Rittenberg (1938) were able to attack chitin. 

 Some of the bacteria could obtain both their energy and nitrogen require- 

 ments from purified chitin, whereas others needed supplementary carbon 

 or nitrogen compounds. Chitinoclastic bacteria were found in nearly all 

 5-gram samples of bottom deposits. They were most numerous at the 

 mud surface, decreasing in abundance with core depth. 



Most of the 31 pure cultures of chitinoclastic bacteria isolated from 

 marine materials by ZoBell and Rittenberg were small, Gram-negative 

 rods. Many produced yellow, brown, orange, or pink pigments. One 

 violet pigment producer resembling Chromohacter violaceum was observed. 

 It, like some of the other chitinoclastic bacteria, had marked attachment 

 propensities, growing almost exclusively tenaciously attached to strips of 

 chitin. None of the chitinoclastic bacteria were able to digest cellulose, 

 and as a class they were feebly saccharolytic. They were active at tem- 

 peratures as low as 0° C. Anaerobic as well as aerobic chitinoclastic bac- 

 teria occur in the sea. 



CO2 and ammonia are end products resulting from the bacterial decom- 

 position of chitin. Acetic acid and reducing sugars have been detected in 

 cultures as intermediate products. 



Hock (1940) isolated chitinoclastic bacteria from marine sands, mud, 

 water, decomposing crabs, and the intestinal contents of animals which 

 feed on crustaceans. Shells of Limulus, the horseshoe crab, were decom- 

 posed relatively rapidly when buried in beach sand. Hock (1941) 

 described two new species of marine chitinoclastic bacteria, Bacterium 

 chitinophilum and Bacterium chitinochroma. 



Chitinoclastic bacteria were demonstrated in the mud and water of 

 alpine lakes by Steiner ( i 93 i ) . Chitin was attacked both aerobically and 

 anaerobically by raw cultures. From Lake Mendota mud, Kinkel (1936) 

 isolated 13 t3^es of chitinoclastic bacteria representing several different 



