[en] Protopectinase will be of potential use in industry. The strain of protopectinase-producing Aspergillus sp. XZ-131 was mutagenized by 15 keV N⁺ ion implantation, with a dose range of 0.52 x 10¹⁵ ion/cm² to 4.68 x 10¹⁵ ion/cm². From the ion implanted Aspergillus sp. XZ-131, the Strain Z-25, which yields high activity protopectinase, was screened out. The protopectinase activity increased by 179% and the protopectinase (U/g dry cell) increased by 84%. In addition, the exponential phase of Aspergillus sp. Z-25 was 24 hours shorter than the Strain XZ-131. The Aspergillus sp. Z-25 yielded high protopectinase activity during stationary phase, the highest protopectinase activity was achieved after 72 h fermentation. (authors)

[en] Radiation screened 98 isolates from 3032 cfu on 56 infusion sets were studied for radiation resistance. The D₁₀ values of these screened isolates were 0.8 to 4.0 kGy and mostly ranged within 1.2 to 1.6 kGy. The microorganisms with D₁₀ ≤ 1.6 kGy were about 99.0% of the total bio-burden. All of the screened isolates were gram-positive bacteria, and 84 isolates were classified as Bacillus sp. and 14 isolates were characterized as Micrococcus sp.. One isolate with D₁₀ of 4.0 kGy (from D-6 = 24 kGy) was found outside of the infusion sets, accounting for 0.033% of the total bio-burden. The most resistant bacteria were orange colony and were classified as a Micrococcus sp. with broad shoulder