Effect of molasses on the production and activity of dye-decolorizing peroxidase from Geotrichum candidum Dec1

The production of dye-decolorizing peroxidase (DyP) was investigated by cultivating Geotrichum candidum Dec1 using molasses as a carbon source. Molasses at concentrations greater than 10 g.l(-1) was found to increase the decolorization activity of the culture broth toward dye, reactive blue 5 mainly because the amount of enzyme produced was enhanced. However, complete inhibition of DyP activity by molasses was observed at the concentration of 20 g.l(-1), indicating that the inhibitory effect of molasses on the culture broth activity to decolorize the dye was involved. When the culture broth was diluted 25 times, the dye-decolorizing activity was 7 times as much as that of non-diluted culture broth. The molasses fractions separated by gel chromatography (300-400 ml and 400-500 ml fractions) completely inhibited the purified DyP. On the basis of these results, we propose a scheme to control both positive and negative effects of molasses on the dye decolorization process.     

Efficient production of a heterologous peroxidase, DyP from Geotrichum candidum Dec 1, on solid-state culture of Aspergillus oryzae RD005

The productivity of a peroxidase (DyP) originating from Geotrichum candidum Dec 1 was enhanced in the solid-state culture using Aspergillus oryzae RD005. When the humidity, water content, and temperature were adjusted to 60%, 50% and 27°C, respectively, the productivity of DyP reached 5.3 g per kilogram wheat bran, which was used as the solid medium. The yield of 5.3 g per kg wheat bran corresponded to the yield of a 56 kg submerged culture. The productivity per gram carbon of the medium in the solid-state culture was 4.1-fold that in the submerged culture.     

Stable repeated-batch production of recombinant dye-decolorizing peroxidase (rDyP) from Aspergillus oryzae

Recombinant Aspergillus oryzae expressing a dye-decolorizing peroxidase gene (dyp) was cultivated for repeated-batch production of recombinant dye-decolorizing peroxidase (rDyP) using maltose as a carbon source. High-level rDyP activity in limitation of carbon and nitrogen sources was maintained stably for 26 cycles of repeated 1-d batches of A. oryzae pellets without any additional pH control. Cultures maintained at 4 degrees C for 20 d resumed rDyP production following a single day of incubation. One liter filtrated crude rDyP containing 4600 U rDyP decolorized 5.07 g RBBR at the apparent decolorization rate of 17.7 mg l(-1) min(-1).     

Effect of molasses supplementation on the production of lactating dairy cows fed diets based on alfalfa and corn silage

Adding sugar to the diet has been reported to improve production in dairy cows. In each of 2 trials, 48 lactating Holsteins (8 with ruminal cannulas) were fed covariate diets for 2 wk, blocked by days in milk into 12 groups of 4, and then randomly assigned to diets based on alfalfa silage containing 4 levels of dried molasses (trial 1) or liquid molasses (trial 2). In both studies, production data were collected for 8 wk, ruminal samples were taken in wk 4 and 8, and statistical models were used that included covariate means and block. In trial 1, experimental diets contained 18% CP and 0, 4, 8, or 12% dried molasses with 2.6, 4.2, 5.6, or 7.2% total sugar. With increasing sugar, there was a linear increase in dry matter intake (DMI), and digestibility of dry matter (DM) and organic matter (OM), but no effect on yield of milk or protein. This resulted in linear decreases in fat-corrected milk (FCM)/DMI and milk N/N-intake. There was a linear decrease in urinary N with increasing sugar, and quadratic effects on milk fat content, yield of fat and FCM, and ruminal ammonia. Mean optimum from these quadratic responses was 4.8% total sugar in these diets. In trial 2, experimental diets contained 15.6% crude protein (CP) and 0, 3, 6, or 9% liquid molasses with 2.6, 4.9, 7.4, or 10.0% total sugar, respectively. Again, there were linear declines in FCM/DMI and milk N/N-intake with increasing sugar, but quadratic responses for DMI, yield of milk, protein, and SNF, digestibility of neutral detergent fiber and acid detergent fiber, milk urea, urinary excretion of purine derivatives, and ruminal ammonia. Mean optimum from all quadratic responses in this trial was 6.3% total sugar. An estimate of an overall optimum, based on yield of fat and FCM (trial 1) and yield of milk, protein, and SNF (trial 2), was 5.0% total sugar, equivalent to adding 2.4% sugar to the basal diets. Feeding more than 6% total sugar appeared to depress production.     

糖蜜废水生物制氢研究进展

利用糖蜜等有机废水制取氢气这种清洁可更新能源，正倍受关注。综述了目前国内外生物制氢技术各个方面的研究进展和成果，论述了研究的发展方向。     

糖蜜酒精废液回用中重金属对酒精发酵的影响

以甘蔗亚硫酸法、碳酸法的几种典型糖蜜为原料,对糖蜜酒精废液中主要的三种重金属元素Fe、Cu、Zn在发酵过程中的影响进行单因素试验。采用原子吸收分光法测定了不同糖蜜的金属元素含量,采用双浓度流程利用酵母菌发酵酒精。在此基础上对发酵原料添加不同量的各重金属元素,考察它们对发酵的抑制点,得出各元素对糖蜜酒精发酵的抑制点为：Fe^3 600～700、Cu^2 11～13、Zn^2 1200(mg／L),并初步探讨了重金属在发酵中的生化作用机理。     

废蜜的化学组成与生物制氢

利用甜菜制糖废蜜、废水作为底物进行连续流生物制氢，既可回收废物又能生产能源。着重阐述了甜菜废蜜中的主要成分及其在生物制氢反应中对微生物的作用。     

山药过氧化物酶的特性及抑制研究

以愈创木酚为底物,470nm处测定山药过氧化物酶(POD)的活性,研究了温度、pH、底物浓度、酶浓度、抑制剂和激活剂对其活性的影响。结果表明,山药过氧化物酶的最适反应温度为60℃,最适反应pH为6.0,Km=0.08231mol/L,Vmax=541.518U/(g·min);五种抑制剂对POD的抑制作用由强到弱依次为:VC>L-Cys>NaHSO3>柠檬酸>EDTA,两种激活剂对POD活性的激活作用由强到弱依次为:CuSO4>FeCl3。     

甘蔗糖蜜预处理对产L-苹果酸的影响与培养基N源添加

研究了经煮沸、活性炭、亚铁氰化钾、磷酸与硫酸预处理的糖蜜对黄曲霉生长与合成L-苹果酸的影响以及培养基中N源添加。以经各种预处理的糖蜜培养黄曲霉,其生物量大小分别是:硫酸法>磷酸法>亚铁氰化钾法>活性炭法>煮沸法。硫酸能有效除去糖蜜中影响菌体生长的胶体物质,用硫酸处理的糖蜜作培养基时,其菌体生长量比煮沸处理高25%。用硫酸与亚铁氰化钾联合处理,对L-苹果酸合成最有利,其产酸达到59.6g/L。糖蜜培养基需添加1g/L硫酸铵为N源,较适培养基配方(g/L)为:糖120,NH4(SO4)21,K2HPO40.15,KH2PO40.15,CaCO370,pH5.5。     

甘蔗糖蜜酒精废液中总黄酮含量的测定

以芦丁为标准物质 ,用分光光度法测定了甘蔗糖蜜酒精废液中黄酮类化合物的含量。此法排除了废液中其他物质的干扰 ,重现性好 ,平均回收率达 97.2 3% ,是一种较为快速的测定废液中总黄酮含量的新方法。为废液中黄酮类化合物的提取和开发利用提供了理论依据。     

回用糖蜜酒精废液中砷、铅对酒精发酵的影响

采用双浓度流程利用酵母菌发酵酒精 ,以甘蔗亚硫酸法、碳酸法的糖蜜为原料 ,对其酒精废液中主要的两种有毒元素 Pb、As在发酵过程中的影响进行单因素试验。采用原子吸收分光法测定了糖蜜的 Pb、As含量 ,在此基础上对发酵原料添加不同量的 Pb、As元素 ,考察各元素对发酵产酒的抑制点 ,初步得出各元素对发酵的抑制点为 As3+3mg/L、Pb2 +2 1m g/L。     

利用耐高渗透压酵母以糖蜜为原料生产甘油

通过一般发酵法得到的乙醇产品在发酵醪中大致产生 13g/L甘油。这个产量不适宜开发利用 ,利用耐高渗透压酵母 (Hollandia、Fleischmann)通过调整发酵条件例如渗透压 (水的活度 )、pH、温度、酵母接种量生成甘油。结果表明 ,在发酵条件为 3 9 9°bx、pH8 7、3 8℃、接种量 12 0× 10 6 个 /mL ,甘油产量可提高到 5 6g/L。此技术的应用会给发酵法生产乙醇的工厂带来巨大的经济效益     

甘蔗糖蜜酵母废液焦糖色素提取工艺研究

采用吸附树脂从酵母废液中提取焦糖色素。1m3废液可提取12kg焦糖色素,该产品质量达到GB8817-1988标准,同时排放废水的COD由10～14万mg/L降至1万mg/L,pH值由4.5～5.0升至7。     

糖蜜酵母废水提取焦糖色素的研究

本文以糖蜜酵母废水为原料，用AB-8大孔树脂吸附焦糖色素，经70％乙醇液洗脱，得到的焦糖色素稳定性好，色率为61578．9EBC，废水色率降低了78．18％，COD下降了80％以上。     

三像草汁与糖蜜混合发酵生产酒精的研究

为了合理利用三像草汁中的糖分,选用酿酒酵母GJ2008作为发酵菌种,通过三像草汁与糖蜜混合发酵的方式生产酒精。研究结果表明,在初始总糖18.0%～20.0%(m/v)左右,pH4.5,发酵温度32℃,不添加营养盐和氮源的条件下,可获得较优的发酵结果,发酵酒精度在11.0%(v/v)左右,发酵效率达到90%。     

甘蔗糖蜜澄清处理及处理前后组分分析

甘蔗糖蜜作为糖厂生产过程中主要的副产品,含糖量高,且含有多酚和黄酮类等抗氧化性成分,可充分利用研制出高附加值的新产品。但由于糖蜜成分复杂,严重影响糖蜜深加工产品品质,因此需要有针对性地进行澄清处理去除胶体、杂质。文章糖蜜澄清处理分为稀释、絮凝、酸解等流程,通过单因素和正交实验,分析确定各工艺流程的条件。糖蜜6倍稀释,添加磷酸和絮凝剂絮凝沉淀,经高速离心机离心分离,收集上层清液。然后在100℃水浴,pH值为2的条件下酸解90 min,使糖蜜中蔗糖尽可能多地转化为还原糖。最后,测定糖蜜澄清处理前后组分含量变化,并采用GC/MS检测分析糖蜜澄清处理前后挥发性物质组分变化。     

甘蓝过氧化物酶活性及其影响因素的研究

甘蓝POD的最适pH为5～6之间;在100℃的热烫温度下随着热烫时间的延长,POD酶活降低,而贮藏2d后酶活的再生量先增大后降低,在热处理时间为1min-1．5min时达到最大值;Na^＋和Ca^2＋显著抑制POD酶活力。因此,当热处理温度为100℃、加热2min,热处理液pH为8,ZnCl2质量浓度为100mg／L,CaCl2质量浓度为300mg／L时,可基本破坏甘蓝中的POD酶活,且甘蓝的质构和色泽较好。     

Calcium modulated activity enhancement and thermal stability study of a cationic peroxidase purified from wheat bran

A cationic form of peroxidase was purified from wheat bran, a major by-product of wheat milling industry to near homogeneity by ammonium sulphate precipitation, anion exchange, and cation exchange and gel filtration chromatography. It was a glycoprotein with a molecular weight of 44 kDa, pH optimum of 4.8 and carbohydrate content of 13.8%. The enzyme showed Ping-Pong Bi Bi type catalysis. Inclusion of calcium during purification increased the specific activity and yield of the enzyme. Activity of purified enzyme was enhanced by calcium more than 400% in a biphasic manner. Purified enzyme exhibited increased thermal stability when calcium was added. There was no change in tryptophan fluorescence by the addition of calcium, but the haem absorption at 403 nm showed a change indicating an alteration in the haem environment. Calcium is essential for maintaining the haem structure, enzymatic activity and thermal stability of wheat bran peroxidase.     

Interaction of molasses and monensin in alfalfa hay- or corn silage-based diets on rumen fermentation, total tract digestibility, and milk production by Holstein cows

Sugar supplementation can stimulate rumen microbial growth and possibly fiber digestibility; however, excess ruminal carbohydrate availability relative to rumen-degradable protein (RDP) can promote energy spilling by microbes, decrease rumen pH, or depress fiber digestibility. Both RDP supply and rumen pH might be altered by forage source and monensin. Therefore, the objective of this study was to evaluate interactions of a sugar source (molasses) with monensin and 2 forage sources on rumen fermentation, total tract digestibility, and production and fatty acid composition of milk. Seven ruminally cannulated lactating Holstein cows were used in a 5 × 7 incomplete Latin square design with five 28-d periods. Four corn silage diets consisted of 1) control (C), 2) 2.6% molasses (M), 3) 2.6% molasses plus 0.45% urea (MU), or 4) 2.6% molasses plus 0.45% urea plus monensin sodium (Rumensin, at the intermediate dosage from the label, 16 g/909 kg of dry matter; MUR). Three chopped alfalfa hay diets consisted of 1) control (C), 2) 2.6% molasses (M), or 3) 2.6% molasses plus Rumensin (MR). Urea was added to corn silage diets to provide RDP comparable to alfalfa hay diets with no urea. Corn silage C and M diets were balanced to have 16.2% crude protein; and the remaining diets, 17.2% crude protein. Dry matter intake was not affected by treatment, but there was a trend for lower milk production in alfalfa hay diets compared with corn silage diets. Despite increased total volatile fatty acid and acetate concentrations in the rumen, total tract organic matter digestibility was lower for alfalfa hay-fed cows. Rumensin did not affect volatile fatty acid concentrations but decreased milk fat from 3.22 to 2.72% in corn silage diets but less in alfalfa hay diets. Medium-chain milk fatty acids (% of total fat) were lower for alfalfa hay compared with corn silage diets, and short-chain milk fatty acids tended to decrease when Rumensin was added. In whole rumen contents, concentrations of trans-10, cis-12 C_18:2 were increased when cows were fed corn silage diets. Rumensin had no effect on conjugated linoleic acid isomers in either milk or rumen contents but tended to increase the concentration of trans-10 C_18:1 in rumen samples. Molasses with urea increased ruminal NH₃-N and milk urea N when cows were fed corn silage diets (6.8 vs. 11.3 and 7.6 vs. 12.0 mg/dL for M vs. MU, respectively). Based on ruminal fermentation characteristics and fatty acid isomers in milk, molasses did not appear to promote ruminal acidosis or milk fat depression. However, combinations of Rumensin with corn silage-based diets already containing molasses and with a relatively high nonfiber carbohydrate:forage neutral detergent fiber ratio influenced biohydrogenation characteristics that are indicators of increased risk for milk fat depression.