SUMMARYAmong the facultative bacteria capable of growth on mesquite wood which were isolated from the asceptically dissected hind-gut of the termite Reticulitermes hesperus were two strains of Bacillus cereus, one strain each of Arthrobacter, Alcaligenes and Serratia, and a very small Gram-negative fermentative rod. The B. cereus strains, the Serratia marcescens strain and the Arthrobacter sp. grew well on a mineral salts a-cellulose agar. One of the Bacillus cereus strains and Serratia marcescens hydrolysed gels of carboxymethylcellulose. All isolates grew well with mesquite wood as the carbon source. The Serratia marcescens isolate produced prodigiosin but differed from a typed strain both in size and in some physiological characteristics.
I N T R O D U C T I O NMesquite brush (genus Prosopis) cannot be digested by cattle in its native form, but aerobic, submerged cultivation of bacteria on the mesquite wood increases the digestible protein and exposes the wood structure to the digestive processes of the ruminant (Thayer et al., 1975). Many sources of bacteria were considered for this process, including the hindgut of the termite. Since wood contains many possible substrates, bacteria capable of utilizing mesquite as their carbon and energy source would not necessarily be cellulolytic.Several species of bacteria which grew rapidly on media containing mesquite wood as the carbon source were isolated from the hind-gut of the termite. One of these species, designated Serratia marcescens RW3, was used in the laboratory for production of single-cell protein (Thayer et al., 1975). This strain and others isolated from the hind-gut possess cellulolytic enzymes (Thayer et al., 1975). In view of their possible commercial application a more detailed study of these bacteria seemed justified. This paper describes the physiological and morphological properties of strains of bacteria isolated from the hind-gut of the termite.
METHODSReticulitermes hesperus was isolated from infested wood in Oklahoma and Texas. Hindguts were dissected aseptically from worker termites which had been washed in Wescodyne antiseptic (West Chemical Products, New York, New York 11101, U.S.A.; U.S. pat. no. 2710277) and then in sterile water to suppress surface bacteria. Samples (0.01 and 0.04 ml) of the hind-gut contents were mixed with physiological saline (0.35 or 1-95 ml, respectively), and spread plates were prepared on BBL Trypticase soy agar (TSA). Cultures were incubated at 30 "C until maximum colony development had occurred. Each colony type was
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