一株降解PHB菌株的分离、鉴定及特性

Separation,Identification and Characterization of A PHB Degrading Stain

本研究从活性污泥中分离筛选出一株高效降解聚–3–羟基丁酸酯(PHB)的菌株PHBd-1,通过形态学和ITS序列分析比对,确定为草酸青霉(Penicillium oxalicum).在以PHB为唯一碳源的培养基上接种培养4 d后,菌落周围出现透明圈.在以PHB为唯一碳源的液体培养基中接入PHBd-1孢子悬浮液,4 d后PHB颗粒降解率达到90%以上,培养液pH由7.20降至2.67,3–羟基丁酸含量在第4天达到最高值.在pH 4.5和温度30℃条件下,培养液中PHB降解酶活力最高.

An efficient PHB-degrading fungus named PHBd-1 was isolated from activated sludge in this study.Through the phylogenetic analysis and BLAST comparison with the fragment of ITS,the PHBd-1 was identified as Penicillium oxalicum.The PHBd-1was inoculated in medium with unique carbon source of PHB and cultured for 4 days.Then a transparent circle appears around the colony on the medium.The spore suspension of PHBd-1 was inoculated in the liquid medium with unique carbon source of PHB.After 4 days,the degradation rates of PHB particle were more than 90%and the pH of the medium decreased from 7.20 to 2.67.The content of 3-hydroxybutyrate reaches the highest value on 4th day,and the activity of PHB degrading enzyme in the culture medium reached the highest when the pH was 4.5 and temperature was 30℃.