TWO ATTEMPTS UPON IMPROVING AN INDUSTRIAL STRAIN OF ASPERGILLUS ORYZAE THROUGH SOMATIC RECOMBINATION AND POLYPLOIDIZATION

Abstract

1.Improvement of kojic acid producibility through somatic recombination was attempted with the following results:
(1) One white leucineless strong producer and three yellow lysineless weak producers were recovered from a heterozygous diploid which was produced between a white leucineless weak producer and a yellow lysineless strong producer.
(2) One of the segregants obtained from the above mentioned diploid strain produced about fourty percent larger amount of kojic acid than the parental producer, yellow lysineless strain.
(3) In general, the breeding effect through this process did not turn out to be so significant as expected.
2. Protease activity of three haploid, three diploid, one triploid, and one tetraploid strains were compared by wheat bran koji method, with the result that the protease activity of two diploid and one tetraploid strains was significantly higher than any of the haploid ones.