基于漆酶/TEMPO体系的亚麻脱胶探究北大核心CSCD

为推进亚麻纤维的绿色化生产,将漆酶介体系统应用于亚麻机落的脱胶,并引入EDTA增强系统的脱胶效果。文章通过对漆酶/TEMPO脱胶系统中温度、pH值、浴比、时间、漆酶质量浓度、TEMPO质量浓度进行探究,确定了在温度55℃、pH值4.0、浴比1︰20、脱胶时间4 h、漆酶质量浓度1.5 U/mL,TEMPO质量浓度为0.2 g/L的条件下,漆酶/TEMPO体系对木质素的去除效果最好。并在此条件下,辅助添加20 mmol/L的EDTA,脱胶后亚麻表面非纤维素物质明显减少,可观察到单根纤维状态,木质素去除率可达56.74%,且纤维无明显损伤,强力基本保留。     

改性漆酶/谷氨酸体系改善旧瓦楞纸浆物理性能的研究

基于L-苯丙氨酸甲酯盐酸盐和二氧化硫脲分别对漆酶氨基酸残基末端的活性基团羧基(-COOH)和氨基(-NH2)进行改性,通过改变漆酶用量、谷氨酸用量、pH、反应温度和时间等研究改性漆酶/谷氨酸体系处理对OCC浆环压指数和抗张指数的影响。结果表明:L-苯丙氨酸甲酯盐酸盐改性漆酶/谷氨酸体系处理OCC浆的最佳反应条件为:漆酶用量4%,谷氨酸用量2%,pH值7,温度30℃,反应时间3h;二氧化硫脲改性漆酶/谷氨酸体系处理OCC浆的最佳反应条件为:漆酶用量4%,谷氨酸用量1.5%,pH值7,温度40℃,反应时间3h;在最佳反应条件下,L-苯丙氨酸甲酯盐酸盐改性漆酶/谷氨酸体系处理OCC浆与未改性漆酶/谷氨酸的相比环压指数提高16%,抗张指数提高20.7%;二氧化硫脲改性漆酶/谷氨酸体系处理的OCC浆与未改性漆酶/谷氨酸的相比环压指数提高11.5%,抗张指数提高12.8%。     

亚麻粗纱及织物生物酶精练探讨

对亚麻粗纱及织物生物酶精练工艺进行了探讨，研究了酶的种类、生物酶的用量、处理时间对精练效果的影响。实验得出，果胶酶对亚麻中含有果胶质去除效果好，木聚糖酶对木质素作用明显，而漆酶介于两者之间；另外，在生物酶处理最佳pH值和温度条件下，处理时间越长，酶的用量越大，对亚麻精练效果越好。     

酶-物理法提取木薯渣中膳食纤维的工艺研究

对干木薯渣进行物理粉碎,再用α-淀粉酶和糖化酶(中温淀粉酶60℃~70℃)、脂肪酶和风味蛋白酶除去木薯渣中的淀粉、脂肪和蛋白质,得到纯净的木薯膳食纤维并用超声波辅助脱色;通过单因素试验得到了木薯渣化学成分去除率和膳食纤维脱色的最佳工艺条件。化学成分去除的最佳工艺条件为:当α-淀粉酶和糖化酶的质量比1∶6,用量为0.6%,酶解pH=7,酶解时间为120 min,酶解温度为60℃时,淀粉去除率最高;当脂肪酶用量0.21%,酶解pH=7,酶解时间90 min,酶解温度为50℃时,脂肪去除率最高;当风味蛋白酶用量0.6%,酶解pH=4,酶解时间150 min,酶解温度为35℃时,蛋白质去除率最好。脱色的最佳试验条件为:当H2O2浓度为10%,漂白时间40 min,超声功率为60 W,漂白温度50℃时,漂白效果最好。     

胶原蛋白与PAM絮凝剂处理造纸中段废水的研究

研究了胶原蛋白絮凝剂处理造纸中段废水的工艺条件,探究了絮凝剂加入量、反应时间、反应温度、pH值对COD去除率、SS去除率、色度去除率的影响。实验结果表明:调节废液pH值在6,絮凝剂用量在2 mg/L,温度在40℃,反应时间30min,能够沉降废水中大部分悬浮物质,使废水COD明显降低。其胶原蛋白絮凝剂可达到COD去除率59.41%、SS去除率77.12%、色度去除率86.67%,而PAM在其最佳处理条件去除效果达到COD去除52.22%、SS去除率65.91%、色度去除率67.59%,同时使用胶原蛋白絮凝剂比PAM节省1.2元·t-1纸,可见胶原蛋白絮凝剂较优于PAM。     

漆酶/超柔软油精复合处理纯大麻织物的性能

鉴于纯大麻织物手感粗硬、易起皱及柔软性差等问题,探讨了一种漆酶+超柔软油精复合处理纯大麻织物的工艺。在实验过程中,以经向断裂强力、经向硬挺度、毛效作为衡量指标,设计了L16(45)正交实验,研究了漆酶用量、超柔软油精用量、处理时间、处理温度、pH的影响。结果表明:漆酶用量2.0%(omf),超柔软油精用量6.5%(omf),50℃处理75 min,pH=5.5时处理效果最佳,纯大麻织物的经向断裂强力为181 N,经向硬挺度为4.39 cm,毛效为12.8 cm/30 min,与未处理的织物相比,经向硬挺度降低了39%,毛效明显提升,纯大麻织物的性能改善,为后续加工创造了条件。     

云芝漆酶粗酶液在造纸废水深度处理中的应用研究

研究了云芝液培养所产的漆酶粗酶液用于深度处理制浆造纸废水时的主要影响因素:时间、酶用量、pH值、温度等。研究结果表明,漆酶粗酶液可有效对制浆造纸废水进行深度处理,最佳处理条件为:处理时间5h,酶液用量5IU/mL,pH7,温度55℃。在进水CODCr为268mg/L,木素含量为100mg/L,色度为186倍的条件下,处理后出水CODCr为48mg/L,木素含量为16mg/L,色度为10倍。CODCr、木素和色度的去除率分别达82.1%,84%和94.6%。     

响应面法优化植酸酶水解大豆分离蛋白的工艺

以大豆分离蛋白为实验材料,在酶解温度、酶添加量、pH、水解时间等单因素实验的基础上,根据Box-Behnken中心组合实验设计原理,采用四因素三水平响应曲面分析法,依据回归分析确定各工艺条件的主要影响因素,以大豆分离蛋白中植酸的去除率为响应值作响应面。植酸去除的最佳工艺条件为：反应温度44.87℃,酶添加量为8.24%,pH为5.54,反应时间为3.03h。在最佳工艺条件下,植酸的去除率为95.15%,验证实验结果为94.98%。     

复合生物酶处理对苘麻木质素去除的影响

以脱胶煮炼酶CKD(R)为代表的复合生物酶开始被广泛用于苎麻脱胶中,亚麻、黄麻等木质素含量相对高的麻纤维能否采用CKD(R)进行脱胶,木质素去除效果是关键.针对这一问题,文章探讨了脱胶煮炼酶CKD(R)在处理木质素含量相对高的苘麻纤维时木质素的去除情况.实验结果表明,CKD(R)酶对苘麻木质素有一定去除作用,去除率为11.60%;实验还获得了CKD(R)酶处理苘麻的最佳工艺,影响木质素去除的主次要排列次序依次为:处理温度、CKD(R)酶浓度、处理时间;CKD(R)酶处理过程中,木质素的去除率受温度、时间、酶用量3个因素的协同作用.     

漆酶作用下添加对-羟肉桂酸处理APMP废水的研究

在漆酶催化作用下,添加的对-羟基肉桂酸能与化机浆APMP废水中的可溶性木素及其衍生物发生聚合反应,从而生成疏水性的大分子聚合物而沉淀除去.实验表明:在漆酶的作用下添加对-羟基肉桂酸可以有效地除去废水中的可溶性木素及其衍生物,在对一羟基肉桂酸用量为0.066g/L,漆酶用量为14.821U/L,处理温度为25℃,处理时间为1h的条件下废水的处理效果最好,木素的脱除率可达75.9%,CODCr的去除率可达69.1%,色度脱除率为86.7%.     

漆酶对普拉红B的脱色性能研究

从温度、pH值、酶质量浓度、盐、金属离子等因素探讨了漆酶对普拉红B的脱色条件,分析了漆酶的脱色动力学性能。结果表明:在温度60℃,pH值5.5及酶质量浓度0.2 g/L的条件下,漆酶对普拉红B的脱色率达95.5%以上。元明粉对漆酶脱色的影响不大;随醋酸钠和氯化钠浓度的增加,脱色效果下降;PO34-、CO23-、Fe2+、Fe3+对漆酶脱色有一定的抑制作用,漆酶催化染料脱色反应的米氏常数Km值为846.82 mg/L。     

云芝漆酶在牛仔布生物整理中的应用

采用漆酶与酸性纤维素酶协同作用来降低牛仔布生物整理中的返沾色。结果表明:单独添加酸性纤维素酶虽然除毛效果好、剥色明显,但靛蓝染料对牛仔布的返沾色较重。而添加漆酶与酸性纤维素协同整理时,可以显著减少返沾色;当漆酶用量为5.0 g/kg牛仔布时,牛仔布的返沾程度减少83%,协同水洗时间以60 min为宜。牛仔布水洗整理的工厂放大试验显示:漆酶与酸性纤维素酶协同作用,一方面可使牛仔布的返沾色显著减弱,获得独特的“雪花”效果;另一方面还可使工厂废水中的靛蓝含量减少80%,有利于降低环境污染。     

固定漆酶与游离漆酶对造纸废水深度处理的研究

用固定漆酶和游离漆酶对造纸废水进行深度处理,重点分析了两种不同状态的酶在不同反应时间、温度、pH值下对造纸废水的CODCr和色度的去除率。结果表明:游离漆酶在处理废水时,最佳反应时间为8 h,最佳反应温度为55℃,最佳反应pH为5;固定态漆酶在处理废水时,最佳反应时间为6 h,最佳反应温度为50~55℃,最佳反应pH为4;通过对废水处理的效果对比,固定漆酶的优点在于达到最佳效果的反应时间短,酶的稳定性高,温度耐受性强,pH适应性显著增强。     

A SPECTROPHOTOMETRIC ASSAY FOR LACCASE USING o-TOLIDINE

A spectrophotometric method for measuring laccase activity using o-tolidine has been developed. Oxidation of o-tolidine by laccase to a blue colored product corresponded with increases in absorbancies at 366 and 630 nm. This oxidation reaction and increases in absorbance at 366 and 630 nm could also be mimicked using hypochlorite, periodate and UV light in place of laccase. After a lag period, the assay was linear in absorbance with time, although the duration of linear region appeared to be affected by the pH. When assayed from 0.025 to 7 mM tolidine, maximum oxidation of substrate occurred using 3 mM o-tolidine. Oxidation of o-tolidine exhibited a pH dependency and showed an apparent pH optimum at approximately 5.0. The utility of this assay was shown by determining laccase activity in various fungal extracts.     

采用生物酶提高瓦楞原纸强度的研究

采用漆酶-组氨酸的组合方式处理OCC浆,并先后在实验室和纸厂研究此生物处理方式对瓦楞原纸性能的影响。实验室小试研究结果表明,当漆酶和组氨酸的用量分别为0.90 U/g和1.0%(对绝干浆)时,成纸的干湿环压指数分别提高了22.9%和30.3%。中试结果也表明,漆酶和组氨酸用量分别为0.225 U/g和0.10%时,成纸干湿环压指数分别提高14.9%和26.4%,纵横向抗张指数分别提高8.0%和10.7%,耐破指数提高16.4%。同时生物处理在促进纤维分丝帚化方面也有明显效果,经处理的纤维保水值上升了40个百分点,纤维平均孔径和比表面积分别提高了1.1%和5.1%,并且浆料中羧基含量也提高了35.4%。     

改性冰糖橙皮渣对结晶紫及亚甲基蓝的吸附性能

以微波和磷酸双改性制备的冰糖橙皮渣吸附剂与未改性吸附剂对比,研究其对染料结晶紫和亚甲基蓝的吸附能力。考察了吸附时间、pH、吸附剂用量、染料初始浓度、吸附温度对吸附剂吸附能力的影响,并用扫描电子显微镜(SEM)和红外光谱(SIR)表征了吸附剂的特性。结果表明,当pH为7时,分别投入吸附剂0.1 g于浓度为50 mg·L-1的结晶紫溶液中和浓度为100 mg·L-1的亚甲基蓝溶液中吸附1.5 h,30 ℃时对结晶紫去除率由改性前的66.5%提升到99.4%,40 ℃时对亚甲基蓝去除率由改性前的57.1%提升到96.3%。改性冰糖橙皮渣吸附结晶紫符合Langmuir等温模型,吸附亚甲基蓝符合Langmuir和Freundlich等温模型,吸附动力学均遵从准二级动力学方程,表明改性吸附剂比未改性吸附剂具有更好的吸附性能。     

云芝菌固态发酵产漆酶及其对二氯酚脱氯作用的研究

利用云芝菌固态发酵产漆酶,当玉米皮和麸皮的比例为6:4,培养基含水量65%,接种量10%,培养温度30℃时,发酵10 d,漆酶活力可达到1.51×10~5U/g(干曲)。利用云芝漆酶对2,4-二氯酚进行脱氯反应,其适宜温度为35℃,pH 6.0,当底物浓度为1 mmol/L时,反应8 h,2,4-二氯酚的去除率达到95%以上。     

功能化水刺粘胶纤维膜的制备及其在漆酶固定化中的应用

针对现有材料对漆酶的负载率低,负载漆酶后重复使用性能差等缺点,以甲基丙烯酸羟乙酯(HEMA)为单体,采用原子转移自由基聚合(ATRP)技术对工业化生产的水刺粘胶纤维膜进行改性处理,然后将改性后的水刺粘胶纤维膜 (即SV-poly(HEMA))进行Fe³⁺吸附,最后将吸附Fe³⁺后的SV-poly(HEMA)(即SV-poly(HEMA)- Fe(Ⅲ))作为配位法固定漆酶的载体,探究其对漆酶固定化的含量、活性、稳定性和重复使用性能,同时对纤维形貌和结构进行表征。结果表明:SV-poly(HEMA)-Fe(Ⅲ)对漆酶的固定化量达到132.9 mg/g;与自由漆酶相比,固定化漆酶对温度变化(20~70 ℃)表现出更强的抵抗力,对pH值(2.0~7.0)表现出更低的敏感性;将负载漆酶的SV-poly(HEMA)-Fe(Ⅲ)重复使用10次后,漆酶的活性依然保持在55%以上。     

Removal of lipophilic extractives from paper pulp by laccase and lignin-derived phenols as natural mediators

In this paper, we show for the first time that lignin-derived phenols can act as laccase mediators for the removal of lipophilic compounds from paper pulp. These natural mediators represent an alternative to synthetic mediators, such as 1-hydroxybenzotriazole (HBT), that cause some economic and environmental concerns. Unbleached kraft pulp from eucalypt wood, which contained free and conjugated sterols responsible for pitch deposition in the manufacture of totally chlorine free paper, was treated with a fungal laccase in the presence of syringaldehyde, acetosyringone, and p-coumaric acid as mediators. The composition of lipophilic extractives in the pulps after the enzymatic treatment followed by a hydrogen peroxide stage was analyzed by gas chromatography and gas chromatography/mass spectrometry. The enzymatic treatment using syringaldehyde as laccase mediator caused the highest removal (over 90%) of free and conjugated sitosterol, similar to that attained with HBT, followed by acetosyringone (over 60% removal), whereas p-coumaric acid was barely effective. Moreover, recalcitrant oxidized steroids surviving laccase-HBT treatment could be removed when using these natural mediators. Pulp brightness was also improved (from 57% to 66% ISO brightness) by the laccase treatment in the presence of the above phenols followed by the peroxide stage due to the simultaneous removal of lignin.     

Toxin removal during protein extraction from tomato leaves

Protein production from agricultural side streams aids in global crop valorisation. This study aimed to isolate protein from tomato leaves (Solanum lycopersicum) with simultaneous toxin removal for use as a food ingredient. Protein was isolated through three methods; pH precipitation, ethanol precipitation, and a combination of heat coagulation and filtration. Protein yield and purity were determined and protein isolates were tested for presence of the toxins, tomatine and dehydrotomatine. Protein recovery was 6–10% of the original total protein content. The pH precipitation method yielded a powder with the highest purity of 76%, but was least effective at removing toxins. Ethanol precipitation removed toxins most effectively, but gave a low protein purity of 40%. The combination of heat coagulation and filtration gave the optimal result, yielding a high purity protein powder of 71% with 99.7% of toxins removed. However, absolute toxin levels might still be too high and safety assessment of toxin removal will be necessary.Industrial relevanceLeaves can be a good source of protein and Rubisco product from sugar beet leaves is now undergoing EFSA approval. Water lentil (Lemna) protein concentrate has recently been approved. The generally low yield of protein product from 1 kg of (wet) leaves is most challenging in these processes compared to more efficiently obtained isolates from (dry) pulses. The better functionality of Rubisco should compensate for that. Rubisco protein from tomato leaves (Solanum lycopersicum) can also be recovered, although toxins need to be removed to allow for human consumption. This additional hurdle will make industrial implementation more difficult.