固态发酵黑曲霉产单宁酶发酵条件研究

经紫外线诱变黑曲霉菌株筛选出1株高产单宁酶的黑曲霉B0201,利用五倍子为诱导物,固态发酵该菌株得到的单宁酶活力有较大提高。单因素优化试验表明,五倍子用量为8%,初始水分含量为50%,初始pH6.0,温度30℃为优化产酶条件。在优化的条件下,培养96h后产单宁酶酶活力达到了58.2 U/g(干基)。因此,黑曲霉固态发酵产单宁酶具有很大的研究意义及广阔的应用前景。     

Improving Solid-State Fermentation of Monascus purpureus on Agricultural Products for Pigment Production

In the present study, the effects of culture medium and temperature on red pigment production and mycelia growth were evaluated. The maximum red pigment production was found when Monascus purpureus CMU001 was cultivated on potato dextrose broth at 30 °C for 2 weeks. The highest amount of dry weight was achieved when cultivated on tryptone glucose yeast extract medium. Cheap agricultural products and residues were used as substrates for pigment production. Corn meal was the best substrate for pigment production (19.4 U/gds) when compared to peanut meal, coconut residue, and soybean meal. The highest pigment yield (129.63 U/gds) was found when corn meal was supplemented with 8% (w/w) glucose, followed by coconut residue (63.50 U/gds), peanut meal (52.50 U/gds), and soybean meal (22.50 U/gds). Galactose, sorbose, psicose, and mannitol were found to be good supplements next to glucose but not xylitol. Pigment was not stable at high temperature and long exposure to UV. The intensity of red pigment decayed 30.57% and 5.41% after autoclaving and pasteurization, respectively.     

Optimized Production of Tannase from Cashew Testa using Aspergillus niger MTCC 5898

The production of enzymes by bioprocessing is a good alternative to add value to agro-industry residues. Production cost of enzymes, the major constraint in bioprocessing, may be brought down by multifaceted approaches which include the use of cheap agro-residues for the microbial-based production of the enzyme, and the use of cost-efficient aerobic cell growth strategies and anaerobic-combined strategies like solid state fermentation (SSF). The current study investigated the production of tannase by Aspergillus niger CEPC 11 (MTCC 5898) on an abundantly available waste byproduct cashew testa under solid state A. niger growth. The optimum values of parameters obtained through response surface methodology (RSM) were cashew testa (23%), K₂HPO₄ (3.40 mM), sodium chloride (0.47 mM) and temperature (32–35°C). Optimization of the amount of cashew testa, content of the medium and incubation temperature resulted in a 3.02-fold increase from 97.32–301.70 U/g DS of tannase.     

单宁酶固定化及其降低蓝靛果汁口腔染色作用分析

为研究固定化单宁酶对催化蓝靛果单宁水解的影响,本实验对单宁微球固定单宁酶的最佳工艺条件、单宁酶固定化前后结构表征及在蓝靛果果汁水解的应用进行研究。结果表明,经响应面试验得到单宁酶固定化最佳工艺条件为酶质量浓度0.03?mg/mL、戊二醛质量分数0.10%、pH?5.4、固定化时间40?min,此条件下的酶活力回收率为71.78%,比活力为724.72?U/mg;扫描电镜图和红外图谱显示单宁酶很好地固定在单宁微球上。果汁中添加固定化单宁酶水解后,果汁中鞣花酸含量明显提高了29.12%。固定化酶添加量为4mg时,ΔE*ab为3.49;着色能力明显减弱。显微镜观察表明经过固定化酶处理后的果汁能明显降低对舌头黏膜的着色能力。     

Comparison of biological and chemical methods,and internal and external standards,for assaying tannins in Spanish shrub species

Tannin contents of stems, flowers and leaves of four shrub species (Erica arborea, Erica australis, Cytisus cantabricus and Genista occidentalis) were chemically assessed using two colorimetric assays (butanol–HCl and Folin–Ciocalteu) and several standards (tannic acid, purified quebracho condensed tannins (CT) and purified CT extracted from each species). A method based on the biological activity of tannins in the rumen was also used for assaying tannins. Depending on the species, the use of quebracho tannin as standard over‐ or underestimated CT contents, in comparison to the use of the respective internal standard. However, the high correlationship observed between in vitro gas production in the presence or absence of polyethylene glycol (PEG) and CT contents estimated from quebracho suggests that this standard could be used for a quicker estimate of the nutritive value of tannin‐containing plants. Tannin contents obtained by the Folin–Ciocalteu method, using tannic acid as standard, were also related to their activity on rumen fermentation. The use of the in vitro gas production technique, in the absence or presence of PEG, may provide more useful information than the chemical assays when the final aim of tannin analysis is to assess the nutritive value of feedstuffs for ruminants. Copyright © 2004 Society of Chemical Industry     

Tannase improves gallic acid bioaccessibility and maintains the quality of mango juice

The effect of tannase on gallic acid (GA) bioaccessibility and auto-oxidative browning of mango juice was investigated. After 2 h of simulated gastric digestion, the concentration of bioaccessible GA increased (P < 0.05) 94.3 ± 7.0% in juice treated with 0.5 U mL⁻¹ tannase while juice not treated with tannase had only a 6.3 ± 3.4% increase in GA. During 2–10 h of simulated intestinal digestion, tannase treated juice continued to have a higher concentration (P < 0.05) of bioaccessible GA in comparison to juice that was not treated with tannase. The use of 167 U 100 mL⁻¹ tannase while processing mango juice did not result in any differences (P < 0.05) in browning measured at 420 nm, yet there was significantly higher (P < 0.05) GA in mango juice post-storage. Processing mango juice with tannase can help improve the bioaccessibility of mango polyphenols without hindering the quality of juice during storage.     

毕赤酵母单宁酶工程菌在固、液发酵中的性质差异分析

探究固、液发酵方式在重组毕赤酵母单宁酶工程菌的形态、产酶量及酶学特性等方面的差异。研究发现，重组菌株在固、液发酵方式下表现出了较大差异。固态发酵条件下，重组菌株能够积累更多的生物量，当培养48 h后积累的生物量比液态发酵高22.3%；经电镜分析发现，固态条件下，重组菌株个体之间更容易出现聚集，并伴随着有生物膜的产生；在不同甲醇体积分数诱导下，固、液发酵的重组菌株的产酶量均出现了先升高后降低的趋势，而诱导两者最高产酶量的甲醇体积分数却存在差异，分别是2%和3%。进一步研究发现，固、液发酵条件下，重组菌株发酵的单宁酶酶学性质也存在一定差异，固、液态发酵单宁酶的最适反应温度分别为30 ℃和为20 ℃，且酶的热稳定性也有一定提高，其余酶学性质差异不显著。经十二烷基硫酸钠-聚丙烯酰氨凝胶电泳分析发现，固态发酵生产的单宁酶存在不同的修饰，这可能是造成上述性质差异的原因之一。综上所述，本研究探究了固、液发酵条件下，重组单宁酶毕赤酵母菌株生长及产酶特性的差异，为高效制备单宁酶提供了一定的理论指导。     

黑曲霉N5-5产单宁酶的酶学性质与固定化

本实验室自主分离的黑曲霉N5-5所产单宁酶已发现对没食子酸丙酯具有良好酶解效果。为了单宁酶的工业化应用,本次研究大批量培养单宁酶,探究其对单宁酸的酶解效果及酶的固定化效果。发酵采用先液体扩培后固体发酵的形式,提酶后利用陶瓷膜过滤技术纯化、浓缩酶液,并对比冷冻干燥和喷雾干燥两种不同干燥方式,还使用树脂载体对酶进行固定化。实验表明,纯化后单宁酶酶活达258.53 U/mL,可水解10%至50%浓度的单宁酸,其中30%以下底物浓度酶解效果较好;冷冻干燥对酶活影响不大而喷雾干燥使酶活降为174.02 U/mL;另外,单宁酶通过树脂载体固定化后,在实验条件下可重复使用至少4次。研究为提高黑曲霉N5-5发酵所产单宁酶的媒介效率、降低酶解反应成本、实现商业化生产建立了理论基础。     

Asp.niger No.3液态发醇生产单宁麽酶条件的研究

研究不同碳源、氮源种类和比例及不同起始pH值等因素对黑曲霉生产单宁酶的影响;并考察了豆粕+NH4NO3分别与单宁、K2HPO4的交互作用。结果表明不同碳源、氮源种类和比例、不同起始pH值等因素对黑曲霉生产单宁酶的影响较大,单宁1.25,小麦粉0.35,豆粕0.67％,NH4NO30.05％,K2HPO0.035,pH6.0为产酶的适宜条件,最高酶活达到144.25U/100ml发酵液,酶比活为17.71。豆粕+NH4NO3、单宁、小麦粉对产酶有极显著影响;豆粕+NH4NO3与K2HPO4的交互作用极显著,与单宁的交互作用显著。本文还探索了菌丝生长与产酶的关系,结果表明黑曲霉产单宁酶属于生长偶联型。     

产单宁酶海洋短梗霉的分离筛选及酶学性质的研究

单宁酶能水解单宁物质中的酯键,在食品和饲料工业中有重要应用价值。 该研究从海洋微生物中获得了几株高产单宁酶 菌株,其中菌株95水解圈与菌落（直径）大小的比值最大,对其进行生理生化鉴定,并扩增内转录间隔区（ITS）序列作进化树分析, 鉴定菌株95号为Aureobasidium subglaciale,其在发酵培养基中发酵72 h达到最大酶活力323.2 U/mL。 考察了温度和pH对酶促反应 影响,同时考察了粗酶的热稳定性和pH稳定性。 结果表明,菌株95号所产单宁酶最适反应温度为50 ℃,该酶在30 ℃、40 ℃、50 ℃水浴 保温4 h,相对酶活80%以上,具有较好的热稳定性;最适反应和最稳定pH均为6.0,在pH 3.0～7.0之间均有较高的酶活,表示其具有 较广的pH值稳定性。     

Effect of substrate and fermentation conditions on pectinase and cellulase production by <Emphasis Type="Italic">Aspergillus niger</Emphasis> NCIM 548 in submerged (SmF) and solid state fermentation (SSF)

The present study deals with the optimization of substrate and fermentation conditions for the production of both pectinase and cellulase by Aspergillus niger NCIM 548 under same fermentation conditions in submerged fermentation (SmF) and solid state fementation (SSF) using a central composite face centered design of response surface methodology (RSM). As per statistical design, the optimum conditions for maximum production of pectinase (1.64 U/mL in SmF and 179.83 U/g in SSF) and cellulase (0.36 U/mL in SmF and 10.81 U/g in SSF) were, time 126 h, pH 4.6, and carbon source concentration 65 g/L in SmF and were time 156 h, pH 4.80, and moisture content 65% in SSF. The response surface modeling was applied effectively to optimize the production of both pectinase and cellulase by A. niger under same fermentation conditions to make the process cost-effective in both submerged and solid state fermentation using agro industrial wastes as substrate.     

产单宁酶菌株的筛选及选育

为得到高产单宁酶的菌株,从多年种植的茶园、柿子园以及掩埋柿子、五倍子和茶叶的花园土壤中通过平板初筛和三角瓶固体发酵复筛筛选到一株产单宁酶的曲霉菌株DNM1-39,固体培养其产单宁酶活力为1.58U/g。以DNM1-39为出发菌株,经紫外线照射、硫酸二乙酯单独处理和紫外线照射-硫酸二乙酯复合诱变处理,获得突变株UD-6,其产酶活力达2.80U/g。连续传代实验结果表明,该菌株产酶活力不变,性能稳定。     

Comparative study on nutrient and anti‐nutrient changes in Ikivunde and Inyange,two Burundian traditionally processed cassava products

A comparative study on nutrients and anti‐nutrients in Ikivunde and Inyange and a correlation of nutrients and anti‐nutrients with fermentation time during processing of both products were carried out. In Ikivunde, all nutrients and anti‐nutrients had high negative correlations with fermentation time, except for crude fibre, fats and calcium, which showed high positive correlations. In Inyange, all nutrients and anti‐nutrients were positively correlated with fermentation time, except for starch, ash, zinc, magnesium, calcium, glutamine and alanine. Analysis of variance showed that Ikivunde and Inyange differed significantly (P < 0.05) in reducing sugar, protein, ash, cyanide, phytic acid and tannin contents at various fermentation times. There were also significant differences (P < 0.05) between Ikivunde and Inyange in starch and fat contents at 48, 72, 96 and 120 h, while for crude fibre a significant difference was observed from 72 h until the end of fermentation. At the end of the fermentation period (120 h), Inyange had higher starch, protein, amino acid, reducing sugar, ash, iron, zinc, potassium, sodium, magnesium, fat, cyanide, phytic acid and tannin contents but lower crude fibre and calcium contents than Ikivunde. The results from this study showed that Inyange contains more nutrients and anti‐nutrients than Ikivunde. Copyright © 2006 Society of Chemical Industry     

珍珠番石榴果实中的营养成分与活性物质分析

以湛江河唇珍珠番石榴果实为原料,分析测试了其营养成分及活性成分。结果表明,珍珠番石榴鲜果样品中各主要营养成分的含量分别为水分(88.98±0.04)g/100g,脂肪(0.11±0.01)g/100g,粗纤维(2.27±0.01)g/100g,总糖(5.78±0.02)g/100g,果糖(22.00±0.20)mg/g,葡萄糖(22.05±0.25)mg/g,蔗糖(12.45±0.15)mg/g,柠檬酸(1.68±0.02)mg/g;蛋白质(0.78±0.01)g/100g,含有16种氨基酸和7种人体必需氨基酸,必需氨基酸含量为1 910.32 mg/kg,占总氨基酸的42.02%,必需氨基酸和非必需氨基酸的比值为0.72;灰分含量为(0.50±0.05)g/100g,其中钾、钙、铁等矿质元素含量较高。活性物质成分的含量分别为多糖(5.68±0.02)g/100g,多酚(180.84±0.15)mg/100g,黄酮(193.58±0.01)mg/100 g,维生素C(94.02±0.02)mg/100g。可见,珍珠番石榴含有种类较多的营养活性成分,开发和应用前景广阔。     

Purification and Biochemical Characterization of Tannase from a Newly Isolated Strain of Paecilomyces Variotii

An extracellular tannase was isolated from Paecilomyces variotii and partially purified using ammonium sulphate precipitation followed by DEAE-Sepharose ion exchange chromatography. Paecilomyces variotii is a newly isolated strain obtained in São Paulo, Brazil, from the screening of 500 fungi evaluated for their production of tannase. The tannase was separated into two peaks. SDS-PAGE analysis indicated that the purified enzyme migrated as a single protein band corresponding to molecular mass of 87.3 kDa (major peak) and 71.5 kDa (minor peak). The peaks eluted very close together between 150 and 250 mM NaCl. DEAE-Sepharose column chromatography led to an overall purification of 19.3 fold. The K_m was found to be 0.61 μmol and the V_max?=?0.55 U.mL^?1. Temperatures from 40 to 65°C and pH values from 4.5 to 6.5 were optimum for tannase activity and stability. This tannase could find potential use in the food-processing industry.     

Evaluation of the fixed nitrogen-to-protein (N:P) conversion factor (6.25) versus ingredient specific N:P conversion factors in feedstuffs

BACKGROUND: The crude protein (CP) of feedstuffs is important as an indicator of essential and non‐essential amino acids for livestock. The protein (P) level needs to be known accurately, to minimize the feeding of excess nitrogen (N) and to reduce N pollution. Laboratory methods for determining N content report N from amino acids, but also N from ammonia and from non‐amino acid sources. The determined CP based on 6.25 × N level typically overestimates the true protein of feedstuffs. RESULTS: Determined ingredient‐specific N:P conversion factors k_A, k_P and k were not equal to the standard 6.25 factor. The k_A had the highest value in all ingredients, which leads to the estimation of specific crude protein (SCP), which is closer to true protein (the summation of the total amino acid residues from amino acid analyses). The SCP(k_A) was lower than CP and true protein in all ingredients, demonstrating that CP might overestimate the actual protein in feedstuffs. CONCLUSION: Based on data from 677 feedstuff samples from 2009, it is concluded that the mean k_A should be 5.68 for corn, 5.64 for soybean meal, 5.74 for corn DDGS, 5.45 for poultry by‐product meal and 5.37 for meat and bone meal. Copyright © 2011 Society of Chemical Industry     

四种常用饲料原料生霉后品质变化规律研究

研究了四种常用饲料原料(玉米、豆粕、鱼粉、双低菜粕)霉变过程中的品质变化规律。结果表明粗脂肪、纯蛋白和淀粉随着储存时间的延长一直呈现出递减的趋势;TBA值、以及黄曲霉毒素B1含量则一直呈现出递增的趋势;水分含量和水分活度随着储存时间的延长先表现出递减的趋势,后出现增加的趋势;脂肪酸值(酸价)、过氧化值和挥发性盐基氮含量随着储存时间的延长先表现增加的趋势,后出现递减的趋势;粗蛋白、玉米赤霉烯酮含量随着储存时间的延长没有显著的变化。     

Yield and composition of cell wall residues isolated from various feedstuffs used for non-ruminant farm animals

The contents of cell wall residue were measured in 14 common feedstuffs used for non-ruminant farm animals by utilising a technique involving pronase and α-amylase treatments. Comparison with the contents of neutral detergent fibre (NDF) revealed that the NDF procedure underestimated cell wall contents in the dicotyledonous plant materials. The losses of cell wall material due to the neutral detergent solution were correlated (r=0.931, P<0.01) with the amount of pectic substances present in the cell wall residues of the dicotyledonous plant materials. Cell wall residues were analysed for starch, crude protein, polysaccharides, condensed tannins, sulphuric acid lignin, acetyl bromide lignin, and ash. Condensed tannins in the cell wall residues of sorghum, rapeseed meal and field bean resulted in a large protein contamination (11.3–26.6%) of these residues and to an overestimation of their lignin content. Compositions of polysaccharides are discussed from chemical and nutritonal viewpoints.     

Juice extraction from mango pulp using an enzymatic complex of Trichoderma sp. produced by solid-state fermentation

In this study, 2 Trichoderma strains (T-I and T-II) were evaluated for the production, by submerged (SmF) and solid state fermentation (SSF) of an enzymatic complex with the capacity to degrade the cell components of mango peels, using these as support (in SSF) and source of nutrients. Highest enzymatic activity (7,552.5 units of endo-glucanase/L) was found in T-II by SSF. Efficiency of this crude enzymatic extract in the extraction of mango juice was evaluated, improving the yield up to 79%, representing an alternative to give an added value of mango peels improving the yields of production of mango juice.     

Degradation and metabolism of 14C‐labelled proanthocyanidins from carob (Ceratonia siliqua) pods in the gastrointestinal tract of the rat

The aim of the work was to study the binding, degradation and metabolism of dietary condensed tannins in the gastrointestinal tract of an omnivore. Young pods of carob (Ceratonia siliqua L) were radiolabelled by in vivo feeding of ¹⁴CO₂, trans‐[U‐¹⁴C]cinnamate or L ‐[U‐¹⁴C]phenylalanine. [¹⁴C]Proanthocyanidins (condensed tannins) were extracted with acetone/water (3:1 v/v), isolated on Sephadex LH‐20 and fed to rats by gavage. After 4 and 18 h, 90–94% of the gavaged ¹⁴C was in the gut contents and/or faeces. Much of the gavaged ¹⁴C (57%), predominantly that originally in tannins of high degree of polymerisation (DP), became insolubilised, mainly in the form of protein–tannin complexes. Some of the [¹⁴C]tannins that remained soluble decreased in DP, especially in the small intestine and caecum. A further fraction (12% of the ¹⁴C gavaged) underwent chemical modifications in the gut to form soluble, non‐tannin compounds. Small proportions of the ¹⁴C were found in the liver (1.0–1.5%), urine (1–2%) and ¹⁴CO₂ (1–2%). We conclude that proanthocyanidins are not inert within the gut but undergo various modifications which may affect the nutrition of the animal. © 2001 Society of Chemical Industry