The presence or absence of metulae, the color of conidial heads, and the pink coloring of the conidia on Czapek agar slant cultures containing 0.05 % anisaldehyde can be possibly regarded as criteria and key characters by which to distinguish three taxa, i.e., Aspergillus sojae Sakaguchi et Yamada ex Murakami, A. parasiticus Speare, and A. toxicarius Murakami. One (strain RIB 4018) of the A. toxicarius strains, producing no pink conidia, is now placed in A. parasiticus on the basis of the dark green color of conidial heads in age. A revised synoptic key is provided for the identification of the yellow-green Aspergilli which produce roughened to echinulate conidia.

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In 1944, Sakaguchi and Yamada isolated some characteristic yellow green Aspergillus strains, which produced prominently echinulate conidia and smooth-walled co

The protoplast fusion of Aspergillus sojae was studied to develop a breeding system for the more desirable koji-mo\ds in the production of shoyu (Japanese fermented soy-sauce) with special attention as to their enzyme productivities. Double-marker mutants, as to conidial color and nutritional requirement, were first derived from the parental strains selected from genealogically unrelated A. sojae cultures showing characteristic enzyme-productivities. Protoplasts of the mutants were obtained in high yields by using a combined enzyme-system composed of the enzyme preparation obtained from a culture filtrate of Bacillus circulans IAM 1165 and commercial chitinase (ICN). The protoplasts were fused in PEG 6000. Many of the fused products that grew on minimal regeneration plates were found to be heterokaryons. Stable heterozygous diploids with green conidia were induced from heterokaryons on UVtreatment. One hundred and thirty diploid strains were obtained and their enzyme-productivities were assayed. The activities of both protease and glutaminase were distributed within the range of those of the parents, and in most strains, the sum of the two activities did not exceed those in the cases of the parents. Exceptionally, a few diploids showing well-balanced high productivity of both enzymes were also obtained.The koji-molds play important roles as producers of various hydrolyzing enzymes in the production of shoyu (Japanese fermented soysauce). For example, the protease of kojimolds contributes to the solubilization of the nitrogen constituents, and the glutaminase causes the liberation of glutamate, one of the most important flavor components in soysauce. The breeding of koji-molds has long been investigated in attempts to increase their enzyme-productivities, using mainly two kinds of methods. One kind involves mutation1'2) with several mutagenic agents such as X-rays, ultraviolet light, MNNG and so on, and the other involves crossing.3) The latter method was developed after the finding that kojimolds, Aspergillus oryzae and Aspergillus sojae, have a so-called parasexual life cycle.4)Recently, many reports concerning intraspecific and interspecific protoplast fusion of filamentous fungi including Aspergillusf;'6) Penicillium7) and MucorS) have appeared.Generally, among the koji-molds used for the production of shoyu, sake and miso, protease hyper-producers show low glutaminase activity, and, on the contrary, glutaminase hyper-producers show insufficient protease activity. Therefore, in this study attempted to obtain a new koji-mold showing well-balanced enzymeactivities through protoplast fusion of a protease hyper-producer and a glutaminase hyper-producer. This paper deals with the development of an effective method for the protoplast fusion of koji-molds, and also with some properties of the resultant fusants. MATERIALS AND METHODSOrganisms. The protease hyper-producer used, 2048, which is a mutant ofAspergillus sojae KS, is stocked in our laboratory.The glutaminase hyper-producer used, Aspergillus sojae 2165, whos...