Weight Loss Of Fibers Research Articles

Development And Acceptability of Banana (Esp. Damilig-Musa Acuminata) Fiber as Alternative Source of Natural Fabric

Banana fiber yarn is a natural best fiber derived from the inner bark (or phloem) of banana plants. It is a very eco-friendly material, which also has the advantage of being completely biodegradable. This yarn is also known as banana silk, due to the shiny and silky aspect of the most precious fibers, or Musa yarn, from the Musa genre to which the banana plant belongs. The study will focus on the Development and Acceptability of Banana (Esp. Damilig-Musa Acuminata) Fiber as Alternative Source of Natural Fabric. The panel of experts will evaluate the following namely: DOST personnel, Garments instructor, fashion designer/ textile experts and Faculty and garments fashion and design students of Isabela State University – Ilagan Campus. The purpose of this research is to develop and test the effectiveness of banana (Damilig-musa acuminata), specifically its pseudo-stem. The researcher aims to unlock the following queries: 1. What are the processes used in the production of yarn? 2. What will be the outcome of the develop banana (Damilig-musa acuminata) after the process of fiber extraction in terms of texture, appearance and durability. 3. What will be the assessment and acceptability of the banana yarn (Damilig-musa acuminata) after weaving process is completed in terms of colorfastness, crease resistant and fabric shrinkage The descriptive type of research will applied in the study with the set of survey questionnaire as the main instrument in gathering data. The weighted mean will also utilizes to determine the general acceptability of the study. The study will use the five-point Likert rating scale. The process will conduct in accordance to Development and Acceptability of Banana (Esp. Damilig-Musa Acuminata) Fiber as Alternative Source of Natural Fabric. The procedures are harvesting, peeling, retting, and sun drying, grouping, spinning and weaving. Evaluation results will show that the project obtained an overall mean of 4.38 to the development of fiber and 3.45 to the level of acceptability of fabric which means that the Development and Acceptability of Banana (Esp. Damilig-Musa Acuminata) Fiber as Alternative Source of Natural Fabric is Moderately Acceptable to the panel of experts based on the criteria checklist. Based on the results of the experiments, it can be concluded that banana fibers can be used as an alternative source of natural fibers because they have several inherent advantages over cotton fiber. Because of the abundance of raw material in nature each year, banana fiber-based yarns and fabrics are less expensive and more sustainable. Because of the low fiber weight and strength loss, softening banana fibers by boiling in distilled water was found to be a better treatment.

Fiber Melt Spinning and Thermo-Stabilization of Para-Rubber Wood Lignin: An Approach for Fully Biomass Precursor Preparation.

Para-rubber wood (PRW) lignin, extracted from agricultural waste, was successfully melt-spun to fibers and thermo-stabilized without employing auxiliary additives. 31P NMR analysis revealed that PRW-lignin contained mainly a syringyl unit of phenolic C5-substituted OH group, which enabled melt flow during fiber spinning, as well as a guaiacyl unit which offered the ability to cross-link during thermo-stabilization. Thermo-stabilized fibers with no fusion were achieved at 250 °C with the heating rate of 0.1 °C/min. Structural changes in the fibers during stabilization were systematically investigated using FTIR and XPS analyses. From the results, changes in the intensities of characteristic bands relating to C-H stretching, aromatic C-H stretching, and C=O stretching indicated structural changes of lignin toward aromaticity via oxidation reactions. XPS analysis of the fibers carbonized at 900, 1000, and 1200 °C revealed an increase in carbon content from 72 to 87 wt %. and a decrease in oxygen content from 28 to 13 wt %. with the increasing carbonization temperature. The weight loss of carbonized fibers was in the range of 73.6 to 88.7%. The high weight loss of fibers carbonized at 1200 °C was explained partly due to the thermal decomposition of disordered carbon. The tensile strength and modulus of carbonized fibers were 163.0 and 275.1 MPa, respectively. This study demonstrates an approach to prepare a fully biomass precursor fiber and contributes to the exploration of the potential use of lignin from biomass waste.

Increased dietary fiber is associated with weight loss among Full Plate Living program participants.

Prior studies have demonstrated that an intake of foods rich in dietary fiber is associated with a favorable impact on health status and body weight. However, the association between fiber intake and weight loss has not been well-studied in employer settings. This research aimed to assess the relationship between dietary fiber and weight loss among individuals participating in the Full Plate Living (FPL) program. The 16-week plant-predominant fiber-rich eating program was delivered to 72 employers, primarily in the Southwest U.S., over 3 years (2017-2019). Participants received weekly video lessons, FPL materials, and additional online resources. A retrospective analysis of repeated measures was conducted using participant data obtained from 4,477 participants, of which 2,792 (62.5%) reduced body weight. Analysis of variance with post hoc analysis was used to assess the statistical significance of the changes between baseline and follow-up measures of dietary fiber intake in each of the food categories, specifically the relationship between changes in individual and combined (composite) daily servings of fruits, vegetables, whole grains, beans, and nuts on body weight measures among three groups at follow-up: those who lost, maintained, or gained weight. Multilevel modeling was used to test the hypothesis that increased intake of fiber was associated with greater weight loss. The mean weight loss for the weight loss group was 3.28 kg. As compared to the two other groups, the intake of whole fiber-rich foods at follow-up was significantly higher among the weight loss group with fruits (2.45 servings), vegetables (2.99 servings), beans (1.03 servings), and total fiber composites (9.07 servings; P < 0.001). A significant increase in servings of grains was also noted (P < 0.05). Multilevel modeling demonstrated that a higher total fiber composite (Model 1), as well as higher intakes of either vegetables or fruits (Model 2), resulted in greater weight loss. Our findings indicate that the FPL program can be a part of a lifestyle medicine approach to healthy eating and weight loss. Delivering the program in clinical, community, and workplace settings can increase its reach as an effective and low-cost offering.

Surface Modification and Mechanical Properties Improvement of Bamboo Fibers Using Dielectric Barrier Discharge Plasma Treatment.

The effect of argon (Ar) and oxygen (O2) gases as well as the treatment times on the properties of modified bamboo fibers using dielectric barrier discharge (DBD) plasma at generated power of 180 W were investigated. The plasma treatment of bamboo fibers with inert gases leads to the generation of ions and radicals on the fiber surface. Fourier transform-infrared spectroscopy (FTIR) confirmed that the functional groups of lignin and hemicellulose were reduced owing to the removal of the amorphous portion of the fibers by plasma etching. X-ray diffraction analysis (XRD) results in an increased crystallinity percentage. X-ray photoelectron spectroscopy (XPS) results showed the oxygen/carbon (O/C) atomic concentration ratio increased with increasing treatment time. The fiber weight loss percentage increased with increased treatment time. Scanning electron microscopy (SEM) images showed that partial etching of the fiber surface led to a higher surface roughness and area and that the Ar + O2 gas plasma treatment provided more surface etching than the Ar gas treatment because of the oxidation reaction of the O2 plasma. The mechanical properties of fiber-reinforced epoxy (FRE) matrix composites revealed that the F(tr)RE-Ar (30) samples showed a high tensile strength, whereas the mechanical properties of the F(tr)RE-Ar + O2 sample decreased with increased treatment time.

Structure of an Alkaline Pectate Lyase and Rational Engineering with Improved Thermo-Alkaline Stability for Efficient Ramie Degumming.

Alkaline pectate lyases have biotechnological applications in plant fiber processing, such as ramie degumming. Previously, we characterized an alkaline pectate lyase from Bacillus clausii S10, named BacPelA, which showed potential for enzymatic ramie degumming because of its high cleavage activity toward methylated pectins in alkaline conditions. However, BacPelA displayed poor thermo-alkaline stability. Here, we report the 1.78 Å resolution crystal structure of BacPelA in apo form. The enzyme has the characteristic right-handed β-helix fold of members of the polysaccharide lyase 1 family and shows overall structural similarity to them, but it displays some differences in the details of the secondary structure and Ca2+-binding site. On the basis of the structure, 10 sites located in flexible regions and showing high B-factor and positive ΔTm values were selected for mutation, aiming to improve the thermo-alkaline stability of the enzyme. Following site-directed saturation mutagenesis and screening, mutants A238C, R150G, and R216H showed an increase in the T5015 value at pH 10.0 of 3.0 °C, 6.5 °C, and 7.0 °C, respectively, compared with the wild-type enzyme, interestingly accompanied by a 24.5%, 46.6%, and 61.9% increase in activity. The combined mutant R150G/R216H/A238C showed an 8.5 °C increase in the T5015 value at pH 10.0, and an 86.1% increase in the specific activity at 60 °C, with approximately doubled catalytic efficiency, compared with the wild-type enzyme. Moreover, this mutant retained 86.2% activity after incubation in ramie degumming conditions (4 h, 60 °C, pH 10.0), compared with only 3.4% for wild-type BacPelA. The combined mutant increased the weight loss of ramie fibers in degumming by 30.2% compared with wild-type BacPelA. This work provides a thermo-alkaline stable, highly active pectate lyase with great potential for application in the textile industry, and also illustrates an effective strategy for rational design and improvement of pectate lyases.

Isolation and Characterization of Muntingia Calabura Cellulose Nanofibers

ABSTRACT Bio-nanocomposite attracts a lot of attention in composite studies and in this article is observed the composite with cellulose nanofiber (CNF) reinforcement. Several types of potential fiber as reinforcement have been published and there is one type of interesting fiber due to its large population, namely Muntingia calabura, which is considered as agricultural waste. Muntingia stems also have the characteristics of being easy to dry, elastic, and soft which are potential to be used as a composite. In order to have high fiber performance, the manufacture of cellulose nanofibers needs to be analyzed for their characteristics. The characteristics of Muntingia fiber were enhanced by applying the chemical treatment using 8% of NaOH and 0.5% of NaClO. Next, mechanical treatment using an ultra-fine-friction grinder was performed to derive the CNF from the fiber. The chemical treatment roughened the fiber surface and decreased the impurities, lignin, and hemicellulose in the fiber. It was proven by the lignin bond chain (C-C) with the smallest intensity of 31.03% and the surface morphology was observed through SEM. The highest crystallinity index of Muntingia fiber was obtained from bleaching-treated Muntingia of 83.29%, affecting the percentage of total fiber weight lost by 28.75%. The lower the percentage of fiber weight loss, the higher the thermal resistance. This study showed that Muntingia fiber is potential to be used as one of the alternative fibers for bio-nano composite.

Multi-Objective Optimization and Analysis of Mechanical Properties of Coir Fiber from Coconut Forest Waste

As a type of natural fiber with excellent elongation, coir fiber has been applied in a wide range of fields. To ensure superb performance, coir fiber is usually treated with alkali before being applied. Previous studies paid little attention to the multiple alkali treatment of coir fiber; however, this study focuses on its influence on the mechanical properties of coir fiber and conducts multi-objective optimization and analysis of the tensile strength, elastic modulus and elongation of coir fiber. Our objective is the comprehensive enhancement of the mechanical properties of coir fiber. In this study, the experimental design is based on the Box-Behnken design method, and three treatment parameters were selected for the study, namely NaOH concentration, treatment time and treatment temperature. Analysis of variance (ANOVA) was adopted to analyze the experimental data, and response surface methodology (RSM) was used to investigate how the treatment factors interact with each other and affect the responses values. To improve the tensile strength, elastic modulus and elongation of coir fiber simultaneously, the experimental parameters were optimized. The results showed that the optimal values of NaOH concentration, treatment time and treatment temperature were 4.12%, 15.08 h and 34.21 °C, respectively. Under these conditions, the tensile strength of coir fiber was 97.14 MPa, the elastic modulus was 2.98 GPa and the elongation was 29.35%, which were 38.28%, 39.91% and 25.59% higher than that of untreated coir fiber, respectively. Furthermore, scanning electron microscopy (SEM), thermogravimetric analysis (TGA-DTG), Fourier-transform infrared spectroscopy (FTIR) and X-ray diffraction (XRD) were used to analyze the changes in surface, weight loss, composition and crystallinity of coir fiber treated with alkali under optimum conditions compared with untreated coir fiber to obtain a deeper insight into the influential mechanisms of alkali treatment.

Effect of TiO2 on preparation condition, mechanical properties and alkali resistance of continuous basalt fibers

The low alkali resistance of basalt fiber limits its utilization in the strong alkaline environment such as cement and concrete as the reinforcing material. Adding additive in the basalt rocks is the feasible method to enhance the alkali resistance. However, it is necessary to develop the efficient additive for basalt fiber. In this work, the effect of TiO2 on the preparation condition, alkali resistance and mechanical properties of basalt fiber was investigated. The preparation conditions were studied by DSC, XRD and high-temperature rotational viscometer. Then the corrosion behavior of TiO2-basalt fibers in NaOH solution was studied via SEM/EDX, FIB/SEM and FTIR. The results indicated that the viscosity of basalt melt decreased significantly with the increasing TiO2 content from 0% to 2%, but the crystallization tendency was not changed with TiO2 below 2%, the upper limit for TiO2 addition. The tensile strength increased by 20–60% because Ti4+ promoted Al3+ into the network structure and intensify the polymerization by entering the network structure as network precursor in the form of [TiO4]. Meanwhile, TiO2 in the basalt fibers formed insoluble titanium hydroxide, so the weight loss of TiO2-basalt fibers in NaOH solution was reduced up to 50%. Through FIB/SEM/EDX, the corrosion of basalt fiber in alkali condition is controlled by ion diffusion. The outward diffusion of Fe, Mg and Ti to the surface of fiber formed the insoluble layer, so the rate of substitution reaction between the OH− and basalt fibers was slowed down, but it also leaded to the non-uniform corrosion.

Properties of Microfibers of Various Compositions as a Component of Cellular Composites

The paper presents studies on the properties of various types of micro-reinforcing fibers to assess their role and effectiveness in the structure formation of the cellular composite. Based on the data on the weight loss after exposure in a model medium of cement, analysis of the alkali resistance of fibers of five different types – basalt fiber, heat-treated basalt fiber, polymer fiber and glass fibers from two different manufacturers – was carried out. It is shown that the fibers have a sufficiently high durability in the medium of hardening cement, which is expressed by a relatively insignificant weight loss of the original fiber after exposure in a model medium for 28 days in ambient conditions. The weight loss for some fibers sharply increases when hardening conditions are changed to hydrothermal ones. The images of fibers exposed in a model medium of cement, obtained using scanning microscopy, were also analyzed, and the character of distribution of acidic and basic adsorption sites on the surface of fibers depending on the type was assessed. Based on the analysis of the obtained data, we can talk about a high number of active sites on the surface of basalt and glass fibers, which ensures the formation of crystalline new formations on them and makes it possible to predict their high adhesion to the cement matrix.

Zr-rich basalt continuous fibers with increased alkali resistant properties

Zirconium-rich basalt continuous fibers with zirconium oxide content from 5.1 to 8.1 wt% with the addition of 1% lanthanum oxide were obtained in a laboratory facility. The production temperature range were measured. It was shown that lanthanum oxide addition allows to decrease production temperature by 50° and to make wider the production temperature range by 10°. Weight loss and tensile strength loss of fibers after refluxing in alkali solution were determined. The weight loss after boiling in 1 M NaOH and 0.5 M Na2CO3 solution is comparable to the weight loss of zirconium-rich glass fibers (AR glass). The addition of lanthanum oxide leads to an increase in the tensile strength of Zr-rich basalt continuous fibers by 15–20%. Based on the obtained data, it can be concluded that the presented approach will not only improve the alkali resistance of basalt continuous fibers for reinforcing cements and concretes, but also significantly reduce their cost.

Comparative Analysis of Alkaline and Enzymatic Degumming Process of Hemp Fibers

In this study, a comparison between alkaline and enzymatic degumming process of hemp fibers has been carried out. Degumming of hemp fibers is essential to remove the lignin content and to segregate the individual fibers for textile grade applications. In this research, optimization of degumming process parameters was carried out to reduce the strength loss in fibers. The percentage weight loss of hemp fibers after the degumming process was studied. Two approaches comprising alkaline and enzymatic methods were used. Hemp fiber diameter was determined along with the single fiber strength before and after the degumming process. Stiffness is directly linked to fiber diameter. Therefore, the fiber diameter was also taken into consideration for optimization of the degumming process. The chemicals used in alkali degumming were sodium hydroxide, magnesium sulfate, hydrogen peroxide, and magnesium chloride. Alkali degumming was the best-suited degumming method for segregating the individual hemp fibers. The optimized parameters obtained for alkali degumming method were heating time 50 min and heating temperature 75 °C. Enzymatic degumming is an eco-friendly method, but the result obtained does not provide a better separation of fibers and fine fiber diameter.

Soil Degradation Characteristics of Short Sisal/PLA Composites

Abstract Fully biodegradable composites were made-up of short sisal leaf fiber as a reinforcing member and Polylactic acid (PLA) as matrix. The biodegradation rate of untreated sisal/PLA (UTS/PLA) and successive alkali treated sisal/PLA (10TS/PLA) composites was found by evaluating the weight loss, mechanical strength and surface roughness before and after soil burial test. The results revealed that UTS/PLA composites have degraded much rapidly than that of 10TS/PLA composites. It is found that there was a loss in weight of 15.20% for UTS/PLA with 25% of fiber content and weight loss of only 5.56% with 10TS/PLA composites after keeping the samples for 90days in soil. The surface roughness on composites was predicted with ‘Ra’ value and increase in surface roughness of the composite was observed with increase in fiber loading and the increment was slightly high for 10TS/PLA compared to that of untreated fiber composite as well as pure PLA. After burial of composites in the soil for 90days, a huge drop in the tensile strength was observed for both UTS/PLA and 10TS/PLA composites. The drop is 26.5%, 54% and 56.31% for plain PLA, UTS/PLA and 10TS/PLA composites respectively. From the experimentation it is confirmed that PLA and its composites can be subjected to degradation in soil at a reasonable speed and also it is recommended that the amount of degradation within a span of time can be controlled by fiber treatment with alkali as well as fiber loading.

The effect of concrete alkalinity on behavior of reinforcing polyester and polypropylene fibers with similar properties

The use of fiber reinforced concrete (FRC) has received wide attention in recent years. Alkalinity affects polyethylene terephthalate (PET) fibers. Therefore, the use of PET fibers in an alkaline environment such as concrete is faced with uncertainties. In this work, three types of PET and polypropylene (PP) fibers with similar physical and mechanical properties were used as concrete reinforcement. In order to simulate the alkaline environment of concrete, hydrolysis of PET and PP fibers was carried out in 60 °C solution of NaOH 10% at pH = 14 for 1, 2, and 4 h duration. Fiber properties such as diameter, mechanical properties and moisture regain both before and after being subjected to alkaline hydrolysis were measured. Probable degradation of the fibers due to alkaline hydrolysis was evaluated using SEM and FTIR. The fibers were used in concrete at the same fiber volume fraction of 0.55%. FRCs were cured for 28 days and compressive, tensile and flexural strength were measured. Results showed that in initial stages of alkaline treatment severe weight loss of PET fibers occurred but beyond a certain time the rate of weight loss increased, slows down. Although mechanical properties of PET fibers in alkaline environment deteriorated due to weight reduction phenomenon, but results in generation of advantages such as hydrophilicity and creation of dimples on the surface of the treated fibers that enhanced adhesion properties of the fiber-matrix.

Comparison of the Structure and Properties of Wool and Cashmere Fibres under Potassium Permanganate Treatment

In this study, the weight loss and tensile property of wool fibers and cashmere fibers before and after various potassium permanganate solution treatment were investigated. The scale morphology and crystallization index of the original and treated fibers were analysed with scanning electron microscopy and X-ray diffraction analysis. The experimental results showed that the weight loss of wool fibers is more than that of cashmere fibers under low potassium permanganate content treatment, but is less than that of cashmere fibers under high potassium permanganate content treatment. The force loss of cashmere fibers increased linearly with an increase in potassium permanganate content. The scales of cashmere fiber were damaged at a potassium permanganate content of 9%, but the scales of wool fiber were clear. The relative crystallisation index of treated wool is twice as that of treated cashmere at a potassium permanganate content of 9%.

On the Oxidative Ablation and Mechanical Properties of T300 Carbon Fibers at Elevated Temperatures

Abstract Carbon fibers are the main component and load carrier within many high-temperature composites. Oxidative ablation of carbon fibers is the main failure mechanism of high-temperature composites and significantly affects the mechanical properties of the composites. The effects of the ablation of carbon fiber at high temperatures on carbon fiber mechanical properties, nevertheless, have not been systematically studied in the available literature. In the present investigation, the oxidative ablation behavior of carbon fibers from room temperature to 900°C has been systematically investigated by employing a thermogravimetric analyzer and in situ video detection. Detectable carbon fiber weight loss was initiated when the temperature was elevated to 600°C within the air environment. The video images showed that the color of the carbon fiber surfaces changed dramatically and then the fibers disappeared gradually, indicating that the carbon fibers underwent a chemical reaction, i.e., oxidative ablation. The static mechanical strength of carbon fiber at various temperatures was investigated and was found to start decreasing significantly at temperatures above 500°C, even though no obvious oxidative ablation occurred. X-ray photoelectron spectroscopy (XPS) and Raman spectrum reveal that the microstructure transition from graphite to nongraphite carbon is the main reason for strength reduction.

The effect of alkali treatment under various conditions on physical properties of kenaf fiber

Alkali treatment was known as one commonly used treatment for natural fiber and obtained a good fiber matrix adhesion, thermal and mechanical properties of composite. This paper reports the effect of alkali treatment conditions on the physical properties of kenaf fiber such as density, weight loss, diameter, cross sectional and fiber morphology. In this study, kenaf fiber were treated under various conditions alkali concentration at 2, 6 and 10 (w/v%), immersion duration at 30, 240 and 480 minute and immersion temperature at 27, 60 and 100°C. The effects of alkali treatment on kenaf fiber physical properties under various conditions were explored. Alkali treatment conditions setting have an impact on kenaf bast fiber physical characteristics. In kenaf fiber density, it was found that a small increase of kenaf density value after alkali treatment compared to untreated kenaf fiber. When each of alkali treatment parameters increased, kenaf fiber density also increased slightly. Kenaf fiber weight loss also exhibit a similar pattern of small increment with the increase of treatment parameters. Additionally, kenaf fiber diameter and cross sectional area show a decline pattern after treated with alkali. Furthermore, this decline pattern was corresponding with the increasing level of alkali treatment parameters. The maximum of kenaf diameter reduction was recorded at high level of each alkali treatment parameters.

Electrospun mullite nanofibers derived from diphasic mullite sol

AbstractFine‐grained mullite nanofibers derived from the diphasic mullite sol were successfully fabricated by electrospinning and subsequent pyrolysis at 1500°C. Polymethylsiloxane and aluminum tri‐sec‐butoxide were selected as the silicon and aluminum source to synthesize the diphasic sol. Results show that the weight loss of mullite precursor fibers in our work was about 60 wt.%, which is similar with that of fibers fabricated using the monophasic sol. This low weight loss was mainly attributed to the high ceramic yield of polymethylsiloxane and low introduced polyvinylpyrrolidone content, which ensures the integrity of fiber morphology during the sintering process. Mullite fibers with 216 nm average diameter were fabricated after sintered at 1500°C and the corresponding grain size was only ~100 nm, much smaller than that in mullite fibers derived from monophasic sols. Therefore, it can be predicated that mullite fibers in this work should possess a higher mechanical strength than those derived from monophasic sols when the sintering temperature was higher than 1400°C and therefore was an ideal starting materials for the fabrication of mullite nanofibrous ceramics used as the high‐temperature thermal insulation materials.

Cloning, evaluation, and high-level expression of a thermo-alkaline pectate lyase from alkaliphilic Bacillus clausii with potential in ramie degumming.

Alkaline pectate lyases (Pels) have potential application in bioscouring of the textile industry. In this study, a thermo-alkaline Pel (BacPelA) gene from an alkaliphilic Bacillus clausii strain was cloned and overexpressed in Escherichia coli. The mature BacPelA exhibited maximum activity at pH10.5 and 70°C and showed high cleavage capability on methylated pectins. BacPelA showed the highest specific activity of 936.2Umg-1 on ≥85% methylated pectin and 675.5Umg-1 on standard substrate polygalacturonic acid (PGA) upon evaluation of the absorbance at 235nm (A235). The K m and k cat values for PGA were 0.54gl-1 and 346.5s-1, respectively. Moreover, the 3,5-dinitrosalicylic acid (DNS) assay, which detects the released reducing oligogalacturonic acids, was confirmed to be inaccurate and unsuitable for endo-acting pectinase activity assay because of the difference in the reducibility by DNS reagent between the standard galacturonic acid and the catalytic oligomer products. Significant ramie fiber weight loss was observed following treatment with BacPelA (24.8%) and combined enzyme-chemical method (30.9%), which indicated that the degumming efficiency of BacPelA was the highest of all alkaline and thermostable Pels reported to date. The total activity of the recombinant mature BacPelA reached 8378.2Uml-1 (A235) by high-cell-density cultivation in fed-batch fermentation with productivity of 239.4Uml-1h-1 using E. coli as host, which represents the highest Pel yield reported to date. Therefore, BacPelA, with promising properties for bioscouring, shows potential applications for ramie degumming in the textile industry.

Characterization and overproduction of a thermo-alkaline pectate lyase from alkaliphilic Bacillus licheniformis with potential in ramie degumming

Abstract A thermo-alkaline pectate lyase (BliPelA) gene from an alkaliphilic Bacillus licheniformis strain was cloned and overexpressed in Escherichia coli . Mature BliPelA exhibited maximum activity at pH 11 and 70 °C, and demonstrated cleavage capability on a broad range of substrates such as polygalacturonic acid, pectins, and methylated pectins. The highest specific activity, of 320 U mg −1 , was towards polygalacturonic acid. Significant ramie ( Boehmeria nivea ) fiber weight loss (21.5%) was obtained following enzyme treatment and combined enzyme-chemical treatment (29.3%), indicating a high ramie degumming efficiency of BliPelA. The total activity of recombinant BliPelA reached 1450.1 U ml −1 with a productivity of 48.3 U ml −1 h −1 under high-cell-density cultivation with a glycerol exponential feeding strategy for 30 h in 1-l fed-batch fermenter, and 1380.1 U ml −1 with a productivity of 57.5 U ml −1 h −1 after 24 h under constant glucose feeding in a 20-l fermenter using E. coli as the host. The enzyme yields reached 4.5 and 4.3 g l −1 in 1-l and 20-l fed-batch fermenters, respectively, which are higher than those of most reported alkaline Pels. Based on these promising properties and high-level production, BliPelA shows great potential for application in ramie degumming in textile industry.

The Durability and Performance of Short Fibers for a Newly Developed Alkali-Activated Binder

This study reports the development of a fiber-reinforced alkali-activated binder (FRAAB) with an emphasis on the performance and the durability of the fibers in the alkaline alkali-activated binder (AAB)-matrix. For the development of the matrix, the reactive components granulated slag and coal fly ash were used, which were alkali-activated with a mixture of sodium hydroxide (2–10 mol/L) and an aqueous sodium silicate solution (SiO2/Na2O molar ratio: 2.1) at ambient temperature. For the reinforcement of the matrix integral fibers of alkali-resistant glass (AR-glass), E-glass, basalt, and carbon with a fiber volume content of 0.5% were used. By the integration of these short fibers, the three-point bending tensile strength of the AAB increased strikingly from 4.6 MPa (no fibers) up to 5.7 MPa (carbon) after one day. As a result of the investigations of the alkali resistance, the AR-glass and the carbon fibers showed the highest durability of all fibers in the FRAAB-matrix. In contrast to that, the weight loss of E-glass and basalt fibers was significant under the alkaline condition. According to these results, only the AR-glass and the carbon fibers reveal sufficient durability in the alkaline AAB-matrix.