本文關鍵詞： 香菇菌糠 寡糖 膜分離 枯草芽孢稈菌 發(fā)酵　出處：《昆明理工大學》2017年碩士論文　論文類型：學位論文

【摘要】：菌糠是子實體采收后產(chǎn)生的廢棄培養(yǎng)基,一般包括麥麩、木屑和剩余菌絲體,不加處理隨意棄置或簡單進行焚燒處理,不僅會增加環(huán)境中蚊蠅和病原微生物的數(shù)量,還會釋放糖類、蛋白質(zhì)等污染水質(zhì),造成環(huán)境污染。糖類等膠體物質(zhì)、混凝劑絮體等顆粒物質(zhì)及富里酸等溶解性有機物在飲用水處理過程中會造成膜污染。超濾膜過濾過程中,截留的膠體層主要是水中普遍存在的多糖,而水中的金屬離子如鈣離子和鐵離子會連接不同的多糖分子,使其在膜表面形成比濾餅層結(jié)構更加緊密的凝膠層。本研究以綜合利用的思路,利用膜分離技術,從廢棄物香菇菌糠中最大限度提取香菇寡糖,降低環(huán)境污染,實現(xiàn)對菌糠的高附加值利用。膜分離技術在水處理領域有廣泛應用,具有高效、節(jié)能等特點,非常適合從菌糠中提取寡糖。寡糖分子量介于單糖和多糖之間,即200KD～3000 KD。首先利用超濾可去除溶液中相對分子量大于3000 KD的多糖,再利用納濾膜,除去溶液中相對分子量小于200 KD的單糖。為了提高寡糖得率,從香菇菌糠中篩選出可以降解多糖為寡糖的菌種,采用微生物發(fā)酵香菇菌糠的方法,將香菇多糖降解為寡糖,提高寡糖產(chǎn)量。經(jīng)發(fā)酵后,寡糖產(chǎn)率從原來的0.29%提高到0.71%。本研究涉及香菇子實體糖類提取工藝、卷式膜分離寡糖工藝的優(yōu)化、活性炭脫色、微生物發(fā)酵香菇菌糠四個方面。香菇子實體中寡糖含量較香菇菌糠中含量要高,且試驗干擾因素少,擬以香菇子實體為試材,選擇料液比、浸提溫度、浸提時間進行正交試驗,優(yōu)化寡糖的生產(chǎn)工藝;改變過濾操作壓力和料液pH,優(yōu)化出最佳膜工藝;改變活性炭脫色條件(活性炭添加量、時間、溫度),分離純化寡糖;最后利用微生物的發(fā)酵作用,從菌糠里篩選出可以提高寡糖產(chǎn)量的微生物菌種,經(jīng)過發(fā)酵最大限度提高寡糖提取率。取得的主要研究成果:(1)料液比1:16,提取溫度60℃,提取時間1Omin,在此工藝下從香菇子實體中提取寡糖的產(chǎn)率為1.07%;(2)超濾膜操作壓力0.75MPa,納濾膜1.95MPa,pH為7時為膜處理最佳工藝;(3)活性炭用量0.3g/100mL、脫色時間1Omin、脫色溫度60°C時,脫色效果最好,脫色率為74.1%;(4)從食用菌菌糠中篩選出能夠降解香菇多糖的菌株,經(jīng)16SrDNA序列檢測和比對后,鑒定為為枯草芽孢稈菌,利用該菌株可以大幅增加菌糠提取寡糖的效率,在接種量7.5%,40℃、發(fā)酵48h后,以1:24料液比,50℃浴加熱1Omin時,香菇菌糠中寡糖產(chǎn)率為0.71%,與沒有進行枯草芽孢稈菌發(fā)酵的對照相比,提取率提高2.5倍。
[Abstract]:Bacterial bran is a waste medium produced after harvest of fruiting body. It usually includes wheat bran, sawdust and residual mycelium, and is disposed of at will or simply incinerated without treatment. Not only will increase the number of mosquitoes and pathogenic microorganisms in the environment, but also will release sugar, protein and other pollution of water quality, resulting in environmental pollution, sugar and other colloidal substances. Flocculant flocs and dissolved organic compounds such as fulvic acid can cause membrane fouling in the process of drinking water treatment. The metal ions in water such as calcium ion and iron ion will connect different polysaccharide molecules to form a gel layer which is more compact than the filter cake layer structure on the membrane surface. Lentinus edodes oligosaccharides were extracted from the waste of Lentinus edodes to reduce environmental pollution and achieve high value-added utilization. Membrane separation technology has been widely used in the field of water treatment with the characteristics of high efficiency and energy saving. It is very suitable for extracting oligosaccharides from bacterial bran. The molecular weight of oligosaccharides is between monosaccharides and polysaccharides. That is 200kD ~ 3000KD. Firstly, the polysaccharides with relative molecular weight larger than 3000KD can be removed by ultrafiltration, and then nanofiltration membrane is used. In order to increase the yield of oligosaccharides, the strains which can degrade polysaccharides into oligosaccharides were screened out from the mushroom bran, and the method of microbial fermentation was used to ferment the mushroom chaff of Lentinus edodes. Lentinus edodes polysaccharides were degraded into oligosaccharides and the yield of oligosaccharides was increased from 0.29% to 0.71 after fermentation. Optimization of the separation process of oligosaccharides by coil membrane, decolorization of activated carbon and microbial fermentation of mushroom bran. The content of oligosaccharide in the fruiting body of Lentinus edodes is higher than that in shiitake mushroom bran, and the interference factors are less. In order to optimize the production process of oligosaccharides, orthogonal experiments were carried out with lentinus edodes fruiting body as the material, the ratio of material to liquid, the extraction temperature and the extraction time. The optimum membrane process was optimized by changing the filtration pressure and the pH of the liquid. Changing the decolorization conditions of activated carbon (amount of activated carbon, time, temperature), separation and purification of oligosaccharides; Finally, by using the fermentation effect of microorganism, the microbial strains which can increase the yield of oligosaccharide were selected from the microbial chaff. After fermentation, the extraction rate of oligosaccharides was maximized. The main research result was: 1: 16 ratio of material to liquid, extraction temperature 60 鈩，

本文編號：1442065