Optimization of the Pretreatment of the Mixture of Cassava Peelings and Pineapple Fibers Using Response Surface Methodology and a Process Simulator for the Bioethanol Production

The increase in oil prices and greenhouse gas emissions has led to the search for substitutes for fossil fuels. In Cameroon, the abundance of lignocellulosic resources is inherent to agricultural activity. Production of bioethanol remains a challenge given the crystallinity of cellulose and the presence of the complex. The pretreatment aimed to solubilize the lignin fraction and to make cellulose more accessible to the hydrolytic enzymes, was done using the organosolv process. A mathematical modeling was performed to point out the effect of the temperature on the kinetics of the release of the reducing sugars during the pretreatment. Two mathematical model was used, SAEMAN’s model and Response surface methodology. The first show that the kinetic parameters of the hydrolysis of the cellulose and reducing sugar are: 0.05089 min-1, 5358.1461 J·mol-1, 1383.03691 min-1, 51577.6100 J·mol-1 respectively. The second model was used. Temperature is the factor having the most positive influence whereas, ethanol concentration is not an essential factor. To release the maximum, an organosolv pre-treatment of this sub-strate should be carried out at 209.08°C for 47.60 min with an ethanol-water ratio of 24.02%. Organosolv pre-treatment is an effective process for delignification of the lignocellulosic structure.

Cultivation of Candida utilis on Cassava Peel Hydrolysates for Single-cell Protein Production

The growth ofCandida utilis NRRL Y-1084 in acid and enzymatic hydrolysates of cassava peel and on glucose in a mineral salts medium was investigated in aerobic submerged cultivation. Kinetic and stoichiometric parameters for growth were determined. The cardinal temperatures of this yeast strain were 14 ℃, 33 ℃ and 41 ℃. C. utilis exhibited no absolute requirement for growth factors, although its maximum specific growth rate （μmax） was higher in the mineral salts medium with yeast extract than without, but its biomass yield coefficient （Yx/s） did not differ much in these two media. In the enzymatic hydrolysate, its Yx/s value on sugar was 0.44 with a μmax of 0.35 h^-1, whereas the corresponding values were 0.52 and 0.48 h^-1 in the acid hydrolysate and 0.50 and 0.37 h^-1 in the mineral salts medium without yeast extract. The crude protein content of biomass grown in the glucose medium and the acid and enzymatic hydrolysates were 47.5%, 49.1% and 56.7%, respectively. The amino acid profile of the yeast biomass compared favourably with the FAO standard. Cassava peel hydrolysate has potential as a cheap carbohydrate feedstock for the production of yeast single cell protein by using C. utilis.

Production of Cellulase and Xylanase by Aspergillus terreus KJ829487 Using Cassava Peels as Subtrates

Cassava (Manihot esculenta, Crantz) is one of the most important food plants in West Africa. Its peels are made up of cellulose, hemicellulose and lignin. This lignocellulolytic biomass can be converted using microbial enzymes to fermentable sugars which have wide range of biotechnological relevance in many fermentation processes. The aim of this study is to screen filamentous fungi from decaying cassava peels that are good producers of xylanases and cellulases. Decaying parts of cassava peels were obtained and brought to the laboratory for further work. Fungi were isolated, identified and screened for cellulase and xylanase production. Isolate with highest frequency of occurrence and enzyme production was identified using phenotypic and molecular method. Optimisation of growth conditions for enzymes production was monitored using the DNSA method, also saccharification of cassava peel were carried out using the enzymes obtained from the isolate. Aspergillus terreus KJ829487 was the predominant fungus. It produces cellulases and xylanases optimally at 40°C, pH 6 and 8, utilising carboxymethylcellulose (CMC) or xylose and yeast extracts as its carbon and nitrogen sources respectively. Saccharification of the peels yielded 584 mg/L glucose, 78 mg/L xylose and 66 mg/L rhamnose. Aspergillus terreus KJ829487 obtained from cassava peels have the ability to produce high concentration cellulases and xylanases which effectively hydrolysed the lignocelluloses’ biomass to fermentable sugars.

Production of Lipase Using Cassava Peel and Sunflower Oil in Solid-State Fermentation： Preliminary Study

Full use of residues from industrial processes is a fundamental necessity of contemporary society, since it avoids impacts to the environment by using residues as inputs for other products of high economic and social importance. In this study, lipase production of the crude enzymatic extracts obtained by Aspergillus niger using cassava peel as substrate and sunflower oil as an inductor was investigated. The optimized cultivation temperature and concentration of inductor were determined using the response surface methodology. The two variables studied exercised influence in the production of lipase in the 95% level of confidence. The response surface obtained indicated that the conditions that maximize lipase activity production were 30.5 ~C and initial concentration of sunflower oil was 2.5% （w/w）. Through this analysis, it is evident that extremes in temperature and concentration of inductor tend to decrease lipase production, since low temperatures decrease metabolism and high temperatures may inactivate the lipase. Optimum lipase yield was 59.8 U/g of dry peel which was fermented for 60 h. Lipase production presents a peak of 61.3 U/g, at 72 h of fermentation. However, this value is statistically equal （p 〉 0.05） of the value of lipase activity obtained for 60 h and 84 h of fermentation.

Studies on the Combination of Some Selected Microorganisms for Biodegradation of Cassava Peel Wastes （Manihot Esculenta）

Cassava peel has a lot of nutrients which can be utilized as fertilizer in agriculture. However, high cellulose contents may cause difficulty for organic digestion and slow down the nutrient absorption for plants. This study aims to reach the microorganisms or their combination for biodegradating the cassava peel waste. The initial result shows that after 21 days the glucose concentration in all samples was the highest during experiment times. The reducing glucose produced in mg/mL by the selected bacteria was 9.32, higher than the selected fungie of 1.57 mg/mL. The percentage degradation of cassava peel weigh was the highest for fungi which was 52% of weigh, respectively. Meanwhile, bacteria only degradated about 31.6% after 4 weeks. However, the combination between bacteria and fungi provides the highest glucose concentration, 19.29 mg/mL and digests 62% of the mass cassava in experiment. This study suggests that biodegradation of agro-wastes in the environment to reduce biomass waste pollution is very promising.

Evaluating the Stability of Indigenous Akwadum Soil with Cassava Peel Ash and Quarry Dust

Cassava peels are produced as a waste from cassava, which are disposed into landfills. These become an environmental problem;therefore the use of cassava peel ash (CPA) as a soil stabilizer must be encouraged. This study investigates the effects of CPA and quarry dust (QD) on the engineering properties of Akwadum soil behavior, using compaction test, Atterberg limit, and California bearing ratio (CBR). These properties were compared with those of unstabilized soil (original) and soil stabilized with CPA and QD. The natural soil was obtained from a borrowed pit at Akwadum near Koforidua at an average depth of 0.8 m which is meant for road works. This soil sample was stabilized with CPA and QD at 5%, 10% and 20% respectively. The compaction, California bearing ratio and Atterberg limit test were performed on the stabilized soils to thoroughly evaluate them. The results indicate that increasing the percentage of CPA to the natural soil decreases the maximum dry density at increasing optimum water content. The addition of QD at higher percentage increases the maximum dry density at decreasing optimum water content. The results reveal that both QD and CPA improve the engineering properties of the soil with QD providing better results.

The Potential Use of Cassava Peel for Treatment of Mine Water in Mozambique

In the last decade, Mozambique became one of the top coal producers in Africa. The coal mines are in Moatize district in the center of the country, inside the lower Zambezi river basin. Pollution due to mining activities has negative impacts in agriculture, fishing, water supply, and presents risks to public health. Mozambique is one of the largest cassava producers in the world. More than 1.5 million tons of cassava peel are generated in the country and this agro-waste is discarded. The aim of this study is to discuss the possibility of using cassava peel to treat mine water. Cassava peel can be used as carbon sources for sulfate reducing bacteria in bioremediation, as an adsorbent and as a filter medium. An integrated method is proposed for treatment of mine water in Moatize. It was suggested that applying cassava peel generated in developing countries for treatment of mine water could be a good solution to protect the environment against mining pollution.

Production of Fermentable Sugars from Organosolv Pretreated Cassava Peels

Cassava peels are rich in lignocellulolytic materials which are not readily amenable to enzymatic hydrolysis;hence, there is a need for a suitable pretreatment method that will support enzymatic hydrolysis. This study was designed to investigate lignocellulolytic organisms that would effectively support the bioconversion of organosolv pretreated cassava peels to fermentable sugars. Decaying cassava peels were collected into sterile bottles and microorganisms isolated, characterized and screened for lignocellulolytic enzymes production. Optimum temperature, pH and nutrient sources for enzyme production were determined. Organosolv pretreatment was carried out using methanol with varied concentration of catalyst (0.01 - 3 M), reaction time (15 - 60 min) and substrate size. Crude enzymes (cellulase and xylanase) from the isolates were added to the pretreated peels and bioconversion was monitored by measuring the concentration of reducing sugar and calculating the percentage peel hydrolysis. The fermentable sugars produced were quantified using gas chromatography. Pseudomonas fluorescens and Aspergillus terreus were isolated. P. fluorescens produces 2.8 u/mL of crude enzymes optimally at 50°C and pH 8 while A. terreus produces 3.4 u/mL optimally at 40°C, pH 6. Both isolates utilizes CarboxyMethylCellulose (CMC) and yeast extract as their best carbon and nitrogen sources. Highest percentage of peel hydrolysis was 67% for P. fluorescens at 0.01 M and 0.05 M for A. terreus (94%). Highest concentration of fermentable sugar was produced by A. terreus crude enzyme (331.79 mg/L glucose, 45.3 mg/L rhamnose and 46.52 mg/L xylose). P. fluorescens and A. terreus effectively supported the bioconversion of organosolv pretreated cassava peels to fermentable sugars.

Production of Ethanol from Cassava Peelings Using a Developed Percolation Reactor

Bioethanol is an important product in the fuel market obtainable from biomass through fermentation process but direct conversion of cassava peelings to bioethanol as energy by-product is difficult because of its lignocellulosic content. This paper therefore, considers the intermediate route of converting lignocellulosic biomass to fermentable sugar through acid hydrolysis and consequent ethanol production, in a developed percolation reactor. Cassava tuber consists of the starchy flesh and peelings that can be converted into bioethanol but the main agro-waste from cassava crop, aside from the leaves and stem is the peelings. The level of cultivating of the crop in Nigeria is exceptionally high as practised in other developing nations, yet there is no significant use for its peelings which is generated in thousands of metric tonnes annually. Therefore, apercolation reactor is designed for the thermochemical pre-treatment of the lignocellulosic biomass through hydrolysis process with a view to recovering the reducing sugars for fermentation. The reactor is designed to hold 2 kg of pulverised cassava peelings of 0.5≤ and ≥0.3 mm particle size and circulate 3 L of acid liquor for each hydrolysis run. The reactor comprised of a 0.0261 m3 perforated basket, 1.83 W capacity circulation pump in power rating, and a heating chamber containing 3 kW heater. The reactor is designed to operate within the temperature range of 20°C - 180°C, pressure ≤ 45 Nm?2, and liquor flow rate of 4.33 × 10?4 m3·S?1. The reactor was used to convert 500 g of pulverised cassava peelings to sugar laden hydrolysate that subsequently yielded 118 mL of bioethanol through fermentation process in three replicated experiments. The designed percolation reactor could therefore serve as a veritable tool in converting biomass of lignocellulosic origin to chemical and energy products, reduce wastes and promote cleaner environment.

Cassava Peel Starch as a Raw Material for Polyhydroxyalkanoates Synthesis by Cupriavidus necator

The environmental problems caused by plastics of fossil origin are well known. To reduce harmful impact on the environment, bacterial-based plastics, such as polyhydroxyalkanoates (PHAs), are a promising solution. Microbial PHAs can be produced using abundant and inexpensive agricultural by-products as raw material. In this study, the potential use of Cupriavidus necator 11599 for the bioconversion of cassava starch into biodegradable PHAs was explored. Although Cupriavidus necator 11599 is a well-known PHA producer, it cannot grow directly on starch. Thus, acid hydrolysis was carried out on the starch extracted from cassava peels to obtain fermentable sugars. Optimal concentration of reducing sugars (RSs) was obtained by hydrolysis of cassava peel starch with sulfuric acid concentrations of 0.4 N and 0.6 N, at 95˚C and 4 h. The hydrolyzed starch was used for PHA production in Erlenmeyer flasks using reducing sugars (RSs) concentrations ranging from 10 g/L to 25 g/L. The best RS concentration 20 g/L and 25 g/L gave 85.13% ± 1.17% and 89.01% ± 2.49% of biomass PHA content and biomass concentrations of 8.18 g/L and 8.32 g/L, respectively in 48 hours. This research demonstrates that cassava peel starch as an inexpensive feedstock could be used for PHA production, paving the way for the use of other starchy materials to make bioplastics.

Co-pyrolysis of cassava peel with synthetic polymers:thermal and kinetic behaviors

This research effort focuses on the co-pyrolysis of cassava peels waste and some synthetic polymers towards energy conversion and reducing the volume of these waste fractions dumped on dumpsites.The co-pyrolysis behavior and pyrolysis kinetics of various synthetic polymer wastes/cassava peel blends were investigated by blending cassava peel waste with low-density polyethylene(LDPE),polyethylene terephthalate(PET),and polystyrene(PS)at different weight ratios.The physical characteristics of each sample were investigated and the co-pyrolysis experiments were conducted at a heating rate of 10℃/min from room temperature to 800℃in N_(2)atmosphere in a thermogravimetric analyzer.Subsequent to thermal decomposition,kinetic analysis was done using the thermogravimetric data.Results from physicochemical characterization showed that cassava peel has a relatively lower calorific value of 15.92 MJ/kg compared with polystyrene(41.1 MJ/kg),low-density polyethylene(42.6 MJ/kg),and polyethylene terephthalate(21.1 MJ/kg).The thermal decomposition behavior of cassava peel was seen to be significantly different from those of the synthetic polymers.The decomposition of the biomass material such as cassava peel generally occurs in two stages while the decomposition of LDPE,PS,and PET occurred in a single stage.The activation energy required for thermal degradation in cassava peel was also found to be lower to that of the plastic material.The co-pyrolysis of cassava peel and different synthetic polymers affected the thermal and kinetic behaviors of the blends,reduce the activation energy and residue after pyrolysis.

超声波辅助提取木薯皮活性物质工艺

木薯皮乙醇提取物同时具有抗乙酰胆碱酯酶(AChE)和抗丁酰胆碱酯酶(BuChE)的活性,为了能充分提取和利用其抗胆碱酯酶活性物质,研究了超声波提取木薯皮活性物质的工艺。通过单因素试验和Box-Behnken Design法设计的响应面优化试验确定了超声波辅助乙醇提取木薯皮中抗胆碱酯酶活性物质的最优工艺条件,并比较了超声波提取与传统溶剂浸提的提取效果。试验结果表明:超声波辅助乙醇提取木薯皮中抗胆碱酯酶活性物质的最优工艺条件为:乙醇体积分数为95%,超声波功率550W,提取时间90min,提取温度60℃,液料比12mL/g,在此工艺条件下,木薯皮活性物质的平均得率为8.97%,质量浓度为0.5mg/mL时的AChE抑制率为54.62%,BuChE抑制率为45.7%;影响木薯皮活性物质得率的4个主要因素的显著程度排列顺序为:超声波提取功率>提取温度>提取时间>液料比;与传统溶剂浸提法相比,超声波提取法具有提取速度快,得率高,提取物活性好,溶剂用量少等明显优势。

木薯皮总香豆素活性物质超声波提取工艺优化

为了能充分提取和利用木薯皮香豆素活性物质,研究了超声波提取木薯皮总香豆素的工艺。通过单因素试验和Box-Behnken响应面设计优化试验确定了超声波辅助乙醇提取木薯皮中总香豆素活性物质的最优工艺条件,并比较了超声波提取与传统溶剂浸提的提取效果。试验结果表明:超声波辅助乙醇提取木薯皮中总香豆素活性物质的最优工艺条件为:乙醇体积分数95%,超声波功率550 W,提取时间90 min,提取温度60℃,液料比12 mL/g,在此工艺条件下,木薯皮提取物的总香豆素平均质量比为2.48 mg/g。影响总香豆素含量的4个因素的显著程度依次为:超声波功率、提取温度、提取时间、液料比。与溶剂浸提法(提取时间360 min,液料比16 mL/g,总香豆素2.14 mg/g)相比,超声波提取法具有提取速度快、总香豆素含量高、提取物活性好、溶剂用量少等明显优势。

大戟科木薯皮矿物质及化学成分的波谱分析

首次利用电感耦合等离子体发射光谱研究木薯皮的矿物质的种类及含量,又利用超临界及传统提取方法得到木薯皮不同极性部位的化学成分,并通过气—质联用、红外光谱、核磁共振技术等波谱分析方法对木薯皮化学成分做了初步定性分析。结果表明:木薯皮中矿物质含量最高的是K,含量最高为1 453.29 mg/100 g干重,Ca含量次之,Na含量位居第三;微量元素中Ni含量最高,为87.22 mg/kg干重;木薯皮中检索匹配度大于90%的化学成分中检测出7-氨基-3-苯基香豆素和东莨菪内酯2种香豆素类物质,其它重要的化学成分有β-谷甾醇、乙酰愈创木酮、N,N'-羰基二咪唑、亚硝酸异戊酯等,以上化学成分均为首次在木薯皮中发现。

木薯茎杆及叶化学成分初步研究

目的采用系统预试法对木薯茎杆及叶部分可能的化学成分进行预实验,初步探索木薯叶及茎的化学成分。方法采用试管反应法,对木薯茎杆及叶部分的石油醚、水、95%乙醇提取物进行研究,通过多种指示剂和显色剂的沉淀反应或颜色反应,对木薯叶及茎可能含有的化学成分进行初步研究。结果木薯茎杆及叶中可能含有黄酮类、酚类、糖、香豆素、植物甾醇、三萜类和挥发油等化学成分。结论初步确定木薯茎杆及叶部分含有多种有效成分,为木薯茎杆及叶部分的进一步开发利用提供了实验基础。

经发酵菌处理的木薯皮复配基质对黄瓜幼苗生长和叶绿素含量的影响

利用CM菌、EM菌和酵素菌3种发酵菌堆制木薯皮基质,腐熟的木薯皮基质与砂子按照体积比为10∶0、9∶1、8∶2、7∶3、6∶4共5种比例制作黄瓜育苗基质,研究不同配比及不同发酵菌对黄瓜幼苗生长以及叶片叶绿素含量的影响。结果表明:木薯皮与砂子的体积比为8∶2时,用于黄瓜育苗效果较好。EM菌和酵素菌是适宜作为木薯皮的发酵菌,建议在生产上推广应用。

木薯连续机械式去皮机设计与参数优化

木薯去皮是许多木薯产品加工的首要工序,人工去皮成本高、效率低,难以满足生产要求,为此,设计了一款在上料机辅助下可连续作业的木薯去皮机。为优化作业参数,以木薯长度、木薯直径、去皮机螺旋轴旋转速度作为影响木薯去皮效果的因素,以去皮合格率、断薯率、减重率为评价指标,采用正交试验方法进行试验。结果表明,对木薯连续式去皮机去皮合格率影响程度从大到小依次为螺旋轴转速、木薯长度、木薯直径;对断薯率影响程度从大到小依次为木薯长度、木薯直径、螺旋轴转速;对减重率影响程度从大到小依次为木薯直径、螺旋轴转速、木薯长度。优化后最佳作业参数为螺旋轴转速10 r/min、木薯长度10 cm,木薯直径大于60 mm。

削皮、水洗和干燥温度对木薯淀粉纯度和淀粉糊化粘度的影响(英文)

木薯在热带地区是碳水化合物的主要来源。木薯淀粉的品质受许多因素的影响。本项研究着重探讨淀粉提取过程中 ,削皮、水洗、干燥温度对淀粉纯度、白度和淀粉糊化粘度的影响。结果表明 ,未削皮的淀粉样品色发灰 ,但具有比削皮处理高的峰值粘度、95℃最后粘度、5 0℃时粘度、峰值降和持久性。增加水洗次数 ,不但能增加淀粉纯度 ,还可提高淀粉高峰值粘度、95℃最后粘度、5 0℃时粘度、持久性和糊化温度。不同干燥温度对淀粉白度无影响 ,但淀粉纯度随干燥温度的提高而稍稍增加。通常高的干燥温度有高的峰值粘度、95℃最后粘度、峰值降、5 0℃时粘度和持久性。

不同比例菠萝皮与木薯茎叶混合青贮对发酵品质和瘤胃消化率的影响

研究旨在探究不同比例的菠萝皮和木薯茎叶混合青贮对发酵品质和瘤胃降解的影响。试验设定6个不同木薯茎叶与菠萝皮干物质混合比例处理组,分别为100:0(对照组)、90:10(T1组)、80:20(T2组)、70:30(T3组)、60:40(T4组)、50:50(T5组),充分混合后密闭发酵60 d。同时选取了3头黑山羊,分别抽取其瘤胃液等比例混合体外培养6 h。结果表明:随着菠萝皮添加量的增加,pH值显著降低(P<0.05),同时乳酸和丙酸含量升高(P<0.05)。挥发性氨态氮/总氮菠萝皮添加组显著低于对照组(P<0.05)。在T3组和T4处理组的青贮中,乙酸含量表现最低,丁酸含量在T2处理组最高。经过6 h培养后,菠萝皮的添加显著提升了青贮的消化率(P<0.05),在菠萝皮添加组中(T1~T5),挥发性氨态氮含量显著提高(P<0.05)。综上所述,菠萝皮可以有效提升青贮品质和干物质消化率,并且在T3和T4组表现了较好的青贮品质,因此,在木薯茎叶和菠萝皮混合青贮中,菠萝皮的最佳添加比例为30%~40%。

木薯去皮加工技术研究进展

木薯食品化开发利用是木薯产业多元化发展的重要方向,因木薯皮集中了木薯绝大部分可引起中毒的氰苷,所以木薯去皮是木薯食品化开发利用不可缺少的加工环节,对木薯食品的规模化、产业化发展起着决定性作用。本文概述了近年来国内外果蔬加工产业中的去皮技术和相应去皮设备的工作原理及特点,并对当前木薯去皮技术的研究与发展进行了总结和展望。