离子交换树脂吸附古龙酸的工艺

应用自行合成的阴离子树脂D02直接吸附发酵液中的2-酮基-L-古龙酸,并研究了其吸附的静态与动态过程.利用Langmuir和Freundlich吸附等温线方程对吸附等温线数据进行拟合,发现2种模型相关性都很好.测定了不同流速、温度、浓度以及pH条件下古龙酸在合成树脂柱中的穿透曲线,当上柱液pH为1.5、质量浓度为10 g/L、吸附温度为309 K、流速为0.35 mL/min时,每g湿树脂的动态附容量为133 mg.同时测定了不同洗脱剂、洗脱流速条件下的洗脱曲线.每g湿树脂的动态吸附容量达到了133 mg,当温度为283 K、洗脱剂为10%H2SO4-CH3OH、流速为0.2 mL/min时,洗脱收率可达65.3%.     

麦秆稀酸水解液的脱色脱毒研究

为了充分利用麦秆纤维素,并提高水解液发酵性能,对麦秆纤维素稀酸水解液的脱色脱毒进行了研究,考察了活性炭的用量、反应温度、时间、pH值对水解液的脱色率及还原糖含量的影响。结果表明,脱色的最优条件为:活性炭用量∶水解液体积=2∶1,温度为35℃,时间为60 m in,pH为4.0,在此条件下的脱色率为88.11%,还原糖损失率为48.54%,糠醛的去除率达到74.91%,酚类化合物可以全部去除。     

稀酸水解菊芋制乙醇技术研究

考察了固液质量比、酸浓度、反应温度和反应时间4个条件对菊芋粉稀酸水解的总糖浓度和总糖转化率的影响。结果表明,菊芋稀酸水解的最优化条件为:固液比0.3,硫酸浓度3%,反应温度80℃,反应时间90 min。在此条件下水解菊芋,水解液中的总糖浓度为24.1%,总糖转化率为80.3%;水解液经过中和后,接入酵母菌发酵产乙醇,最终乙醇浓度可达到10.4%,乙醇得率为86.4%。     

酸-碱-酸-碱工艺合成脲醛树脂

以酸-碱-酸-碱工艺合成一种聚乙烯醇(PVA)、三聚氰胺改性脲醛树脂,研究了原料配比、pH值、反应时间等对产品性能的影响。结果发现,当n甲醛:n尿素=1.6:1,聚乙烯醇加入量为甲醛和尿素总质量的1%,三聚氰胺加入量为甲醛和尿素总质量的3%,酸性条件下pH=5.5,碱性条件pH=8.5～9.0,反应温度为80℃左右时,合成的脲醛树脂的机械强度较好,游离甲醛的含量较低。     

pH对水稻秸杆发酵产酸特性的影响

采用锥形瓶反应器及室内培养方法,研究pH对水稻秸杆厌氧产酸的影响。结果表明,酸化产物的组成与pH有关,乙酸和丁酸在不同的pH值下总为主要产物;pH>7时,明显有丙酸生成;酸化的最佳pH值为7,此条件下挥发性脂肪酸(VFA)的产量最高可达11.634 g/L,总固体(TS)的去除率可达51%。     

回转条件下微生物产酶表征

选定3株高产淀粉酶、蛋白酶、纤维素酶的细菌(枯草芽孢杆菌)、放线菌(链霉菌)和丝状真菌(里氏木霉)作为模式菌株,研究了在回转条件下单独发酵产酶及混合培养产酶过程及能力。结果表明,枯草芽孢杆菌、链霉菌和里氏木霉在pH值6.0～7.9之间都可生长。在回转条件下发酵30d,枯草芽孢杆菌维持一定产淀粉酶和蛋白酶能力;链霉菌能够产少量的蛋白酶和淀粉酶;里氏木霉除了具有一定的产纤维素酶能力外,也能产少量的蛋白酶和淀粉酶。将3株菌进行分步混合培养,发酵过程中均能保持较高的淀粉酶活力和蛋白酶活力,在20d和30d的发酵液中检测不到纤维素酶活力。     

甲胺磷废水的酸解-Fenton氧化降解试验研究

采用酸解-Fenton氧化对甲胺磷废水进行预处理试验,研究结果表明:在酸解反应过程中,在pH为2,反应温度100℃的条件下,TOC和硫化物的去除率分别达18.33%和90.7%;在Fenton氧化反应过程中,在pH为4,n(H2O2):n(Fe2+)=30:1,H2O2投加体积分数为3.0%的条件下,TOC去除率达24.3%;投加20%Ca(OH)2乳液,pH为11～12时,可将Fenton氧化后的废水中绝大部分的无机磷除去.     

N-苯基J酸合成工艺研究

以J酸和苯胺为原料,在焦亚硫酸钠介质中缩合制备N-苯基J酸。采用正交法得到较优工艺为n(J酸)∶n(苯胺)∶n(焦亚硫酸钠)=1∶1.5∶3.3,反应液pH=4.5,反应时间15 h;后处理条件为过滤温度T=25℃,过滤时溶液的pH=5.5,酸化废水可连续套用3次;该条件下,反应滤液可连续套用4～5次,每批产品的平均质量为122.2g,纯度95%,收率达91.9%。     

富里酸络氨铜的合成与表征

针对富里酸在农业上的重要作用,合成一种兼具富里酸和铜离子优点的富里酸络氨铜(FA-Cu),将其应用到农作物肥料中,达到绿色环保、低成本的优点。本文采用单因素和正交试验的方法,研究了pH值、富里酸浓度、硫酸铜浓度等因素对合成富里酸络氨铜的质量、纯度、颗粒均匀程度的影响。结果表明:富里酸浓度为3%,硫酸铜浓度为4%,pH值为7时为最佳合成条件,此条件下合成的富里酸络氨铜沉淀颗粒体积较小、分布均匀、没有团簇现象,并通过红外光谱分析和热重分析对产物进行了表征,分析结果表明合成了富里酸络氨铜。     

沉淀转化法回收酸浸渣中铅的酸溶工艺研究

以金精矿焙烧-酸浸除杂后的酸浸渣与碳酸氢铵反应生成的转化渣为原料,进行酸溶浸铅工艺研究。通过正交实验考察了液固质量比、浸出pH和浸出时间等因素对铅浸出率的影响,得到最佳工艺条件：浸出液固质量比为2∶1、浸出液pH=0.5、浸出时间为2 h。在此条件下,金属铅浸出率可达83%。     

PEG/（NH_4）_2SO_4双水相萃取分离茶氨酸的研究

采用聚乙二醇（PEG）/（NH4）2SO4双水相体系萃取分离生产茶多酚所得废液中的茶氨酸,考察了PEG分子量与含量、硫酸铵含量、pH、温度、加盐（KCl、KBr、KI）、茶氨酸含量对双水相及萃取分离茶氨酸的影响。结果表明,PEG/（NH4）2SO4双水相萃取分离茶氨酸的适宜条件是：PEG平均分子量为4 000,质量分数为10%,硫酸铵质量分数为15%,pH约为6,30℃。在此条件下,茶氨酸的分配系数K1=0.16,蛋白质的分配系数K2=0.28,糖类的分配系数K3=9.8,茶氨酸在下相的萃取率为89.5%,可以将茶多酚废液中的茶氨酸与糖类及其他有颜色的杂质分开。     

Application of thermophilic aerobic digestion in protein enrichment of high strength agricultural waste slurry for animal feed supplementation

Thermophilic aerobic digestion (TAD) is a relatively novel waste processing technique with the potential to improve the safety and nutritional value of many agricultural and food industry wastes for use in animal feed supplementation. TAD of model agricultural waste slurry, at soluble chemical oxygen demand (COD) load of approximately 8.0 g L^?1, was implemented to study the effect of the process on crude protein accretion and waste quality. Digestions were carried out under batch conditions at 0.1, 0.25, 0.5 and 1.0 vvm (volume of air per volume of waste slurry per minute) aeration rates and pH 7.0, and at pH 6.0, 7.0, 8.0, 9.0, 9.5 and without pH regulation at 0.5 vvm, all at 55 °C. All reactions were carried out for 156 h using thermophilic populations indigenous to the waste. Digestion at 0.5 and 1.0 vvm led to the greatest degradation of total suspended solids (51.17% and 52.03% respectively) and the highest accretion of crude protein in treated waste (131.28% and 258.94% respectively). Protein content of the digest decreased as digestion pH increased beyond neutral. Slurry soluble protein content decreased with digestion progress, while the ammonium increased early in the process before decreasing progressively. The percentage content of most amino acids in the digest decreased slightly relative to raw waste. The quality of waste protein was comparable with the FAO standard for protein supplement for feed use. Overall, the digested waste was significantly improved relative to the raw waste. With appropriate process optimization TAD has clear potentials for use in the improvement of various wastes for recycling in animal feed. Copyright © 2006 Society of Chemical Industry     

Use of membrane separation in enzymatic hydrolysis of waste paper

A three-stage process containing phosphoric acid pretreatment, enzymatic hydrolysis, and membrane filtration was performed on waste paper as a lignocellulosic material. In the first two stages, the effect of phosphoric acid concentration, enzyme loading, hydrolysis time, and substrate concentration on the amount of products was investigated. At the third stage using a proper membrane, the effect of substrate concentration and transmembrane pressure (TMP) on yield of the reducing sugars was studied. The novelty of the present study was to demonstrate the application of ultrafiltration membrane on the enzymatic hydrolysis process of waste paper. The reducing sugars concentration was determined by using the 3,5-dinitrosalicylic acid (DNS) reagent method. According to the results, a value of 0.5% was determined as the optimum concentration for phosphoric acid in the pretreatment stage. The reducing sugars yield was obtained as 67.4% in this concentration. Moreover, for the enzymatic hydrolysis of waste paper, the suitable amounts of cellulase enzyme loading and hydrolysis time were determined as 50 mg/g substrate and 48 h, respectively. In the filtration stage, increase of substrate concentration and decrease of TMP resulted in higher rejection of the reducing sugars. The experimental results revealed that the highest rejection was 19.2% at TMP of 3 bar and substrate concentration of 100 g/L.     

Assessment of acid hydrolysates of peat as substrate for Scytalidium acidophilum ATCC 26774 fungus

The acid-resistant fungus Scytalidium acidophilum ATCC 26774 was cultivated in submerged fermentation in hydrolysates of Sphagnum peat moss produced with H₂SO₄, HCl, HNO₃ and H₃PO₄ acids. Hydrolysis with H₂SO₄ produced the highest concentration of total carbohydrates and reducing sugars in the hydrolysates. However, when Scytalidium acidophilum ATCC 26774 was grown in undiluted hydrolysates, the H3PO₄ medium produced the best mycelial growth. The H₂SO₄ medium produced the highest dry biomass concentration (3.5 g dm^?3) obtained with water-diluted, non-supplemented peat hydrolysates. Supplementation of diluted H₂SO₄ hydrolysates with 3 g dm^?3 yeast extract and 0.4 g dm^?3 MgSO₄ considerably enhanced the growth, up to 5.9 g dm^?3 dry fungal biomass. The biomass composition of Scytalidium acidophilum ATCC 26774 grown in the medium which produced the best growth was determined, revealing a relatively high protein content of 37.5% of the dry mycelial weight.     

Functional and nutritional characteristics of protein recovered during isolation of chitin from shrimp waste

Shrimp shells are a good source of chitin when processed into chitosans. Only about 10% of the raw material dry matter is recovered as chitosan. The objective of this work is to isolate the protein (during de-proteinization of chitin) using nitric acid 30% (this designated as acidic protein) and 1 M sodium hydroxide (this designated as alkaline protein). The functional properties, amino acid contents and nutritional quality of both isolated protein were evaluated. The acidic protein had significantly (p < 0.05) higher emulsification activity (51.58), emulsification stability (48.15) and foam capacity compared to the alkaline protein. The acidic protein also exhibited a broader range of minimum solubility at pH range 4–6 (from 11.21% to 12.54%). Meanwhile, the minimum solubility (22.89%) of the alkaline shrimp waste protein was quite sharp at pH 4. The highest emulsification activities of acidic protein extract were observed at pH 2 (63.82) and pH 10 (68.76) while the lowest were observed at pH 6 (44.32). The same trend was noticed for the emulsification stability. The emulsification activity of the alkaline protein extract ranged from 31.25 (at pH 4) to 52 (at pH 10) and its stability ranged from 44.21 to 51.12 at the same pHs. The alkaline protein is rich in isoleucin and valine compared to the FAO/WHO reference pattern, while leucine and lysine are slightly deficient compared with the same reference. On the other hand, the acidic protein contains higher amounts of lysine, therionin and valine compared to the reference pattern. The alkaline protein had a higher chemical score and calculated protein efficiency ratio (51.46% and 1.94, respectively) compared to 42.10% and 1.75, respectively for acidic protein.     

Barley grain as carbon substrate for fungal protein production in a farm process

A simple, non-aseptic, submerged aerobic fermentation was sought in which microbial protein could be synthesised from non-protein nitrogen, at the expense of barley carbohydrate, to supplement the protein content of barley grain for non-ruminant feeding. Screening of 23 isolates of fungi in shake flask cultures showed that microbial protein could be successfully produced by a number of different species in a medium containing barley as a source of carbohydrate. Protein synthesis was markedly affected by the addition of different sources of non-protein N to the fermentation; and (NH₄)₂SO₄ or urea proved to be good N sources in this respect. Aspergillus oryzae was selected as the most suitable species for protein synthesis, based on its performance when supplemented with the various N sources. The growth rate of A. oryzae in stirred culture was such that high yields of mycelial protein could be achieved within 24 h from a culture inoculated with a spore suspension. Under the conditions of growth used in these experiments there appeared to be little advantage in adding more than 2% barley to the medium. Higher yields of protein could be achieved at barley concentrations in excess of 2%, but only if the incubation period was extended. The tolerance of A. oryzae to low pH values was exploited to enable fungal cultures to be grown under non-aseptic conditions. Good yields of protein were obtained in 40 litre cultures grown at pH 3.5 in a modified domestic washing machine. Although protein yields were poor, non-aseptic growth was also sucesssful at pH 3.5 in 1000 litre cultures grown in an agricultural feed-mixing vessel.     

扩散渗析-电渗析回收赖氨酸离子交换废液中的盐

为缓解电渗析膜污染,提高电渗析性能,采用阴膜扩散渗析对待脱盐的赖氨酸离子交换废液进行净化处理,对扩散渗析回收的(NH4)2SO4溶液进行电渗析脱盐浓缩。结果表明,当扩散渗析流量为5.6 L/h时,扩散渗析的扩散系数达2.24?10?7 cm2/s,离子交换废液中(NH4)2SO4透过率约为30%,可截留90.1% Mg2+和94.5%有机氮、80.3%蛋白、86.0%总糖、79.3%化学需氧量(COD);与直接电渗析赖氨酸离子交换废液相比,对扩散渗析回收的(NH4)2SO4溶液进行电渗析脱盐浓缩,SO42?膜通量、电流效率分别提高了55.7%和18.3%,操作时间、单位膜通量能耗分别降低了26.1%和42.3%。用扩散渗析净化赖氨酸离子交换废液可有效缓解后续电渗析的膜污染,提高电渗析性能。     

低浓度下己内酰胺-水-硫酸铵-苯体系的液液平衡问题

介绍了在己内酰胺废水中萃取回收己内酰胺的过程中，测定了4套己内酰胺—水—硫酸铵—苯体系的液液平衡数据(水相己内酰胺质量分数小于13％)。实验结果表明，用苯从废水中萃取回收己内酰胺时，pH在2～5．7范围内，pH值升高对回收有利。同时提出了一个简单的关联式并成功地关联上述平衡数据，已用于萃取塔的设计计算。     

Downstream Processes for Aqueous Enzymatic Extraction of Rapeseed Oil and Protein Hydrolysates

Downstream processes following aqueous enzymatic extraction (AEE) of rapeseed oil and protein hydrolysates were developed to enhance the oil and protein yields as well as to purify the protein hydrolysates. The wet precipitate (meal residue) from the AEE was washed with twofold water at 60 °C, pH 11 for 1 h. Emulsions from the AEE and the washing step were pooled and submitted to a stepwise demulsification procedure consisting of storage-centrifugation and freezing–thawing followed by centrifugation. Aqueous phases were pooled and adsorbed onto macroporous adsorption resins (MAR) to remove salts and sugars. Following extensive rinsing with deionized water (pH 4), desorption was achieved by washing with 85% ethanol (v/v) to obtain crude rapeseed peptides (CRPs). In a separate experiment, stepwise desorption was carried out with 25, 55, and 85% ethanol to separate the bitter peptides from the other peptides. Using a combination of the AEE process, washing and demulsification steps, the yields of the total free oil and protein hydrolysates were 88–90% and 94–97%, respectively. The protein recovery was 66.7% and the protein content was enriched from 47.04 to 73.51% in the CRPs. No glucosinolates and phytic acid were detected in the CRPs. From the stepwise desorption, a non-bitter fraction RP25 (containing 64–66% of total desorbed protein) had a bland color and significantly higher protein content (81.04%) and hence was the more desirable product.     

Co-Production of Fungal Biomass Derived Constituents and Ethanol from Citrus Wastes Free Sugars without Auxiliary Nutrients in Airlift Bioreactor

The potential of two zygomycetes fungi, Mucor indicus and Rhizopus oryzae, in assimilating citrus waste free sugars (CWFS) and producing fungal chitosan, oil, and protein as well as ethanol was investigated. Extraction of free sugars from citrus waste can reduce its environmental impact by decreasing the possibility of wild microorganisms growth and formation of bad odors, a typical problem facing the citrus industries. A total sugar concentration of 25.1 g/L was obtained by water extraction of citrus waste at room temperature, used for fungal cultivation in shake flasks and airlift bioreactor with no additional nutrients. In shake flasks cultivations, the fungi were only able to assimilate glucose, while fructose remained almost intact. In contrast, the cultivation of M. indicus and R. oryzae in the four-liter airlift bioreactor resulted in the consumption of almost all sugars and production of 250 and 280 g fungal biomass per kg of consumed sugar, respectively. These biomasses correspondingly contained 40% and 51% protein and 9.8% and 4.4% oil. Furthermore, the fungal cell walls, obtained after removing the alkali soluble fraction of the fungi, contained 0.61 and 0.69 g chitin and chitosan per g of cell wall for M. indicus and R. oryzae, respectively. Moreover, the maximum ethanol yield of 36% and 18% was obtained from M. indicus and R. oryzae, respectively. Furthermore, that M. indicus grew as clump mycelia in the airlift bioreactor, while R. oryzae formed spherical suspended pellets, is a promising feature towards industrialization of the process.