原生质育种筛选可利用泔水发酵生产菌体蛋白饲料的研究

以餐厨垃圾为发酵培养基对9株酵母进行筛选,获得1株非蛋白氮转化率较高的菌株产朊假丝酵母0233,在餐厨垃圾固体培养基中发酵24h后,非蛋白氮转化率为36.69%。对该菌株的原生质体形成与再生的条件进行研究,结果表明:原生质体形成与再生最佳条件为菌龄26h,渗稳剂为含0.1%β-巯基乙醇的0.7mmol/L山梨醇,蜗牛酶浓度2.5%,酶解70min。在此条件下,原生质体形成率为92.80%,原生质体再生率为10.6%。采用He-Ne激光(632.8nm)对产朊假丝酵母0233的原生质体进行反复诱变,得到1株在餐厨垃圾固体培养基发酵后非蛋白氮转化率有较大提高的突变株,其非蛋白氮转化率为56.69%,比出发菌株(产朊假丝酵母0233)的非蛋白氮转化率提高1.6倍。该突变株经多次传代后有较高稳定遗传性,无明显的回复突变。

By using waste food as fermentation medium,a strain named Candida utilis 0233 with high conversion rate of non-protein nitrogen （NPN） was screened out from 9 yeast strains.The formation and regeneration of the protoplast from this strain were studied.The results showed that the 26 h of mycelium age was optimal to forming protoplasts.The formation ratio of protoplasts reached 92.8 % and the regeneration rate was 10.6 % when 2.5 % snail enzyme with 0.7 mol/L sorbierite were used as osmotic stabilizer.A mutant strain was achieved repeatedly by using He-Ne laser（632.8 nm）as mutagen and protoplasts as mutagenesis material.The conversion rate of NPN of mutant strain reached 56.69 % after 24 h fermentation on waste food medium.Stability test showed that the high productivity of the mutant could be inherited stably. There was no obvious reverse mutation after eight subcultures.