By U V mutation , clear-zone method for initial screeing and test of degrading PBS film for re-screening , a m utant strain H J1O with higher ability of degrading PBS film and higher endurance to the temperature and pH valie was obtained from the original strain Alternaria sp . H J03 . Compared with the origmal strain , H J10 had less aenalm ycelium at the begmning of culture , but after 7 days the colony turned com pact and the growth rate was faster . In addition , the herEditary character of higher degrading ability of the mutant was stable after 7 generations, and its degradation rate increased over 14.4％ . The degrading ability of the mutant strain H Jl0 was higher than that of the initial strain at the optimum tem perature (25℃～35℃ ) , even at inappropriate tem perature . Besides, the degradation rate of H Jl0 was also improved at different pH values , especially when the pH value was 5.0 , w hich lincreased by 22 .80％ .%以PBS降解菌HJ03(Alternaria sp.)为出发菌株,通过紫外诱变,透明圈初筛及PBS薄膜复筛,获得一株降解能力增强且对温度和pH耐受力均得到提高的突变株HJ10.与出发菌株相比,HJ10在培养初期气生菌丝少,而培养7 d时菌落致密且生长速度较快.经过连续继代培养7代后发现,突变株的降解活力保持了良好的遗传稳定性,其降解率较出发菌株提高百分比达14.4%以上;在最适降解温度范围内(25 ℃～30 ℃)和不适宜降解的温度条件下突变菌株HJ10的降解率均高于出发菌株;各pH条件下,突变株对PBS的降解能力明显优于出发菌株,尤其在pH 5.0时降解率提高了22.80%.
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