- Volume 32, Issue 1, 1982

A new species of Clostridium isolated from a methanogenic cellulose-enrichment culture of sewage sludge is described. The colonies produced by these bacteria were white, circular, and convex with smooth margins. The cells were straight, spindle-shaped rods, 0.6 by 3.0 μm in size. They were gram negative and nonmotile, and they formed round, terminal spores. A wide variety of carbohydrates was fermented by this mesophilic anaerobe. The major fermentation products were acetic acid, hydrogen, carbon dioxide, and ethanol. The deoxyribonucleic acid base composition was 28 mol% guanine plus cytosine. The name Clostridium saccharolyticum is proposed for this new species on the basis of its broad saccharolytic activity. The type strain of C. saccharolyticum is WM1 (= NRC 2533).

A description is given of a novel member of the yeast genus Pichia that was recovered 13 times in the Sonoran Desert from necrotic tissue of cereoid cacti. Most of the isolates came from organ-pipe cacti. The new yeast occurs in the cactus “rot pockets“ in the haploid condition and is heterothallic. Upon mixing of appropriate mating types, zygotes developed with hat-shaped ascospores. Physiologically, the haploid strains resemble Candida tenuis, but this species has a different habitat and shares only 9.2% of its nuclear deoxyribonucleic acid base sequences with P. mexicana. The sexual state is physiologically similar to P. stipitis and an as yet undescribed cactus-specific species of the genus Clavispora, but their deoxyribonucleic acid sequence complementarity is less than 1% compared with P. mexicana. The base composition of the nuclear deoxyribonucleic acid of P. mexicana ranged from 42.2 to 43.0 mol% guanine plus cytosine (five strains). The type strain of P. mexicana is UCD-FST 76-308A (= ATCC 42175 = CBS 7066) and the complementary mating type is UCD-FST 76-391B ( = ATCC 42176 = CBS 7067).