本文選題：植物乳桿菌 + 噬菌體　； 參考：《內(nèi)蒙古農(nóng)業(yè)大學(xué)》2017年碩士論文

【摘要】：乳酸菌是一類廣泛應(yīng)用于發(fā)酵食品行業(yè)的有益菌種,可以生產(chǎn)乳制品、肉制品以及青貯飼料等產(chǎn)品。而發(fā)酵過程中常常會(huì)有噬菌體侵染到乳酸菌內(nèi),從而導(dǎo)致發(fā)酵過程緩慢甚至發(fā)酵失敗,對發(fā)酵工廠造成巨大的經(jīng)濟(jì)損失。因此,噬菌體的污染被認(rèn)為是食品發(fā)酵行業(yè)存在的巨大威脅之一。本實(shí)驗(yàn)從異常發(fā)酵液中分離并純化了植物乳桿菌烈性噬菌體P2,并以之作為研究對象,分析了其形態(tài)特征、耐受能力、吸附特性,以及不同植物乳桿菌菌株對該噬菌體的敏感性。數(shù)據(jù)結(jié)果顯示,噬菌體P2的頭部是二十面體對稱結(jié)構(gòu),直徑大小約為66.67±3.00 nm,有一條長216.67±3.00 rnn且寬12.25±3.00nm非收縮性尾,屬長尾噬菌體科B1型。該噬菌體的潛伏期為30min,裂解期為135 min,裂解量平均為214.49±3.98PFU。不同的pH值(2～11)對噬菌體P2的存活率有明顯影響,在pH 2、3時(shí)其存活率為0,存活率在pH 6～9可達(dá)80%以上,且在pH 8時(shí)存活率最大;在50℃時(shí)下降到 12.89%。對于噬菌體P2,pH 5～9對該菌體的吸附率沒有明顯影響,均可達(dá)到90%以上。在pH為4、10、11時(shí),噬菌體吸附率雖有所下降,但仍在50%以上。溫度對噬菌體P2的吸附率影響較小,除50℃以外,其他溫度下的吸附率均可達(dá)到88.29%以上。Ca2+對噬菌體P2的吸附能力起到了一定的促進(jìn)作用,而Mg2;則會(huì)在一定程度上抑制噬菌體P2的吸附能力,其提高效果為Ca2+未添加Mg2+。氯霉素對噬菌體P2的吸附能力沒有明顯影響。經(jīng)吸附30min后,吸附率仍可達(dá)到90.19%以上。實(shí)驗(yàn)選用的38株植物乳桿菌菌株中,僅有3株菌對噬菌體P2表現(xiàn)出敏感性,分別是NM20-4、WH6-1-1和NM24-2,說明P2具有較高的侵染特異性。本實(shí)驗(yàn)研究了植物乳桿菌烈性噬菌體P2的生物學(xué)特性,可在豐富乳桿菌噬菌體數(shù)據(jù)庫的同時(shí),為生產(chǎn)過程中對控制該噬菌體提供一定的理論依據(jù)和數(shù)據(jù)支持。
[Abstract]:Lactic acid bacteria (lactic acid bacteria) are a kind of beneficial bacteria widely used in fermented food industry, which can produce dairy products, meat products and silage products. During fermentation, bacteriophage often infects lactic acid bacteria, which leads to slow fermentation and even failure of fermentation, resulting in huge economic loss to the fermentation plant. Therefore, bacteriophage contamination is considered to be one of the great threats in food fermentation industry. The bacteriophage P2of Lactobacillus plantarum was isolated and purified from the abnormal fermentation broth, and its morphology, tolerance, adsorption and sensitivity to the bacteriophage were analyzed. The results showed that the head of the phage P2 was icosahedral symmetrical, with a diameter of about 66.67 鹵3.00 nm, and a non-contractile tail with a length of 216.67 鹵3.00 rnn and a width of 12.25 鹵3.00nm, belonging to the B1 type of the long-tailed phage family. The latent period of the phage was 30 min, the lytic period was 135 min, and the average amount of cleavage was 214.49 鹵3.98 PFU. The survival rate of phage P2 was 0 at pH 2,3, over 80% at pH 6 ~ 9, and the highest at pH 8, and decreased to 12.89 at 50 鈩，

本文編號：1894311