正烷酵母作为饲料的最近研究

本文叙述了近十年来我国对正烷烃酵母研究的进展。我们用的菌种是热带假丝酵母Y-17,本所实验厂的生产规模是年产一百吨酵母。发酵罐为6米~3的内或外循环空气提升式,两级连续发酵,50％废水循环利用。生产能力为2克/升·小时。酵母产品的化学分析,包括蛋白质、氨基酸、脂肪、核酸、维生素等,都证明该产品为一优良蛋白饲料。有毒物质含量(如苯骈(a)芘、重金属)符合国际标准。动物试验(包括用大白鼠、鸡、猪的营养试验,慢性毒性试验,传代试验)证明该正烷烃酵母为安全可靠的优良饲料。我们也研究了酵母的核酸和脂肪的综合利用、并筛选了一株高产新菌株球拟嗜烷烃酵母(新种)4B-2,使生产能力提高至2.8克/升·小时。

Further Studies on n-Paraffin Yeast as Fodder in China

This paper describes the research on production in pilot plant scale of n-paraf-fin yeast in China in recent years.The species used is Candida tropicalis Y-17.Production scaleis 100 tons annually.The fermenter is a 6m~3 air-lift type with an internal or external draft tube.The process is a two-stage,aseptic continuous fermentation with part of the waste fermen-tation fluid recycled.Productivity is 2g/1.h.Content of crude protein of the yeast productafter extraction of nucleic acid and lipid is about 60%.Result of analysis of aminoacid composition showed that it is well-balanced and rich in lysine.It is also rich in vitamin B and nico-tinamide.Contents of toxic substances such as benzo(a)pyrene,aromatic hydrocarbon,mercu-ry,lead and arsenic are below the PAG criteria. We have done a lot of animal tests,including nutritional tests,chronic toxicity tests andmulti-generation tests on rats,chickens and pigs.Some tests last for five years.They all showedthat the n-paraffin yeast has neither toxicity to the parent animals nor cumulative effect ontheir offsprings up to the fifth generation.The n-paraffin yeast is a nutritious and safe fodderfor farm animals. In order to reduce the cost of production of n-paraffin yeast,we have studied the use ofyeast by-product,such as nucleic acid and lipids.The nucleic acids can be used as a growthstimulant for crops.The crude lipid is a good catcher for the flotation of certain kinds of ores.It is also found to stimulate silk spinning of silk worms. Another high yield species of yeast is screened and selected.It is a new species belongingto the genus Torulopsis with a raised productivity of 2.8g/l-h.