Yanni Sudiyani

Chemical characteristics of surfaces of hardwood and softwood deteriorated by weathering

The factors that cause weather-induced deterioration of wood surfaces were determined by chemical and spectroscopic analyses. Albizzia (Paraserianthes falcata Becker.) and sugi (Cryptomeria japonica D. Don) were exposed to two temperate conditions of natural weathering with and without rainfall and to accelerated conditions of artificial weathering coupled with ultraviolet (UV) light irradiation and water flashing. Infrared spectroscopic analysis showed that the oxidative reaction of lignin was observed under all conditions of weathering for both wood species. However, a marked decrease in lignin and hemicellulose content were recognized when albizzia woods were exposed to weathering with water. Lignin content in the softwood sugi did not decrease as much as in albizzia even in the presence of water, but the modification of lignin macromolecules was assumed to be accelerated by water, as seen by electron spin resonance spectroscopy. These results showed that the presence of water promotes the weathering deterioration of wood under UV irradiation.

Infrared spectroscopic investigations of weathering effects on the surface of tropical wood

Abstract Two Fourier transform infrared spectroscopic techniques, photoacoustic and diffuse reflectance spectroscopy, were utilized to explore the physical and chemical changes in wood caused by weathering. Five tropical wood species (albizia, kapur, mahoni, nangka, puspa) were exposed to natural weathering for various periods. The contents of extracts, phenolics, and Klason lignin in unexposed samples of these wood species were determined by chemical analysis. Infrared spectra of the weathered surfaces were recorded by the two techniques. The photoacoustic spectra exhibited rapid decomposition and elusion of wood constituents containing benzene rings in the region closest to the exposed surface. Line maps of infrared spectra in the vertical direction obtained by diffuse reflectance infrared microspectroscopy were consistent with the view that the additive effects of water and ultraviolet irradiation play an important role in destroying the lignin-hemicellulose matrix of the cell wall. The infrared spectroscopic techniques are available for the analysis of weathered wood.

Depth profiling of weathered tropical wood using Fourier transform infrared photoacoustic spectroscopy

Depth profiling analysis of wood samples using Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was carried out to obtain information on the chemical changes caused by weathering. The test samples used for PAS measurements were tropical wood species, puspa (Schima wallichii Korth) and kapur (Dryobalanop lanceolata Burck), that were exposed outdoors for periods of 2–32 weeks. FTIR-PAS spectra of the weathered surfaces were recorded at various moving-mirror velocities in the range from 0.081 to 0.56 cm/s (linear-scan method) to provide the depth profiling analysis. The band intensity of vibrations attributed to phenyl groups clearly decreased as weathering proceeded and demonstrated a tendency to be reduced with a decrease in the photoacoustic probing depth during relatively short weathering periods. The bands of C=O groups also exhibited remarkable spectral changes. The PAS spectra of the tropical wood changed considerably during the 32 weeks of weathering, and their spectral contours gradually approached that of pure cellulose (microcrystalline). It was noted that FTIR-PAS is very useful for depth profiling analysis of the wood surface in the early stages of deterioration.

Changes in surface properties of tropical wood species exposed to the Indonesian climate in relation to mold colonies

Changes in mold populations and genera on the exposed surfaces of tropical hardwoods — albizia (Paraserianthes falcata), kapur (Dryobalanop lanceolata), mahoni (Switenia macrophylla), nangka (Artocarpus heterophyllus), puspa (Schima wallchii) — were investigated. The wood specimens were exposed to the Indonesian climate for 32 weeks. Properties including mass loss, wettability, mold growth (colony-forming units), and mold genera were evaluated. The change in properties after exposure was significantly affected by the wood species, but there was no clear relation between mass loss and the initial chemical components or between wettability and wood density. The number of mold populations was different by exposure period and wood species, but there was no significant effect of climate conditions, such as rainfall and ultraviolet radiation. Of the genera identified,Aureobasidium, Cladosporium, andPenicillium were dominant molds on the exposed wood surfaces.

Optimization pretreatment condition of sweet sorghum bagasse for production of second generation bioethanol

The bagasse residue of Sweet sorghum (Sorghum bicolor (L.) Moench) consist of cellulose 39.48%; hemicellulose 16.56% and lignin 24.77% that can be converted to ethanol. Pretreatment is of great importance to ethanol yield. In this study, pretreatment process was conducted in a 5-liter reactor using NaOH 10% at various temperature 110, 130, 150°C and reaction time 10, 20, 30 minutes and optimizing severity parameter (log R0 between 1.3 - 2.9). The statistical analysis using two way anova showed that third variations of temperature give different effects significant on lignin, hemicellulose and cellulose content at 95% the confidence level. The optimum pretreatment of bagasse sorghum were obtained with Log R0 value between 2.4-2.9. High severity value in pretreatment condition reduce lignin almost 84-86%, maximum reducing lignin content was 86% obtained at temperature 150°C for 20 minutes reaction time and cellulose increased almost two times the initial content.The bagasse residue of Sweet sorghum (Sorghum bicolor (L.) Moench) consist of cellulose 39.48%; hemicellulose 16.56% and lignin 24.77% that can be converted to ethanol. Pretreatment is of great importance to ethanol yield. In this study, pretreatment process was conducted in a 5-liter reactor using NaOH 10% at various temperature 110, 130, 150°C and reaction time 10, 20, 30 minutes and optimizing severity parameter (log R0 between 1.3 - 2.9). The statistical analysis using two way anova showed that third variations of temperature give different effects significant on lignin, hemicellulose and cellulose content at 95% the confidence level. The optimum pretreatment of bagasse sorghum were obtained with Log R0 value between 2.4-2.9. High severity value in pretreatment condition reduce lignin almost 84-86%, maximum reducing lignin content was 86% obtained at temperature 150°C for 20 minutes reaction time and cellulose increased almost two times the initial content.

Bioethanol G2: Production Process and Recent Studies

The demand for ethanol as a substitute of gasoline is rapidly increasing due to the recent increase of imbalance in oil market and interest in environmental issues. First-generation (G1) bioethanol which is currently derived mainly from food crops generate many problems such as net energy losses, greenhouse gas emission, and increased food price. On the other hand, biofuel produced from lignocellulosic materials, so-called second-generation (G2) bioethanol, shows environmental advantages in comparison to G1. The development of bioethanol G2 from lignocellulosic materials possesses many advantages from energy and environmental aspects. Efficient conversion of lignocellulosic biomass to ethanol and value-added biochemicals is still today a challenging proposition. Basically, four steps are included in the production process of bioethanol G2, composed of pretreatment, saccharification, fermentation, and product separation/purification. In each step, there are several ideas to improve its productivity and benefitability. In this chapter, we describe some details about the production process selection or ideas. New studies such as catalytic conversion of lignocellulosic biomass are also rapidly developing, although they are not yet mature to be utilized for industrial purposes.

The effect of two-stage pretreatment on the physical and chemical characteristic of oil palm empty fruit bunch for bioethanol production

This study investigated the effect of two-stage pretreatment using dilute H2SO4 followed by dilute NaOH on the physical characteristic of oil palm empty fruit bunch including crystallinity index, chemical bonding and morphology. Its effect on chemical characteristic, especially the sugar recovery have also been observed. The results showed a low crystallinity degree measured from acid-alkaline OPEFB which was confirmed by the FTIR spectra with the decrease intensity of CH2 bending vibration at 1433 cm-1 and crystallinity index in the amount of 57.53 %. Silica-bodies which was noticed from the raw OPEFB was successfully removed after the sequential pretreatment. High cellulose and lignin removal around 90 % and 73.1 %, respectively with a trace of acetic acid and no furfural content were achieved at the end of the pretreatment.

Extraction of glutathione from EFB fermentation waste using methanol with sonication process

Glutathione is important compound on the human body. Glutathione have a widely use at pharmacy and cosmetics as detoxification, skin whitening agent, antioxidant and many other. This study aims to obtain glutathione from Saccharomyces cerevisiae in fermentation waste of second generation bioethanol. The remaining yeast in the empty fruit bunch (EFB) fermentation was separated from the fermentation solution use centrifugation process and then extracted using a methanol-water solution. The extraction process was done by maceration which was assisted by sonication process. Solvent concentration and time of sonication were varied to see its effect on glutathione concentration. The concentration of glutathione from the extraction process was analyzed using alloxan method with UV-Vis spectrophotometer. The results show that the highest glutathione concentration was approximately 1.32 g/L obtained with methanol solvent at 90 minutes of maceration following with 15 minutes sonication.Glutathione is important compound on the human body. Glutathione have a widely use at pharmacy and cosmetics as detoxification, skin whitening agent, antioxidant and many other. This study aims to obtain glutathione from Saccharomyces cerevisiae in fermentation waste of second generation bioethanol. The remaining yeast in the empty fruit bunch (EFB) fermentation was separated from the fermentation solution use centrifugation process and then extracted using a methanol-water solution. The extraction process was done by maceration which was assisted by sonication process. Solvent concentration and time of sonication were varied to see its effect on glutathione concentration. The concentration of glutathione from the extraction process was analyzed using alloxan method with UV-Vis spectrophotometer. The results show that the highest glutathione concentration was approximately 1.32 g/L obtained with methanol solvent at 90 minutes of maceration following with 15 minutes sonication.

Statistical analysis of NaOH pretreatment effects on sweet sorghum bagasse characteristics

We analyze the behavior of sweet sorghum bagasse characteristics before and after NaOH pretreatments by statistical analysis. These characteristics include the percentages of lignocellulosic materials and the degree of crystallinity. We use the chi-square method to get the values of fitted parameters, and then deploy student’s t-test to check whether they are significantly different from zero at 99.73% confidence level (C.L.). We obtain, in the cases of hemicellulose and lignin, that their percentages after pretreatment decrease statistically. On the other hand, crystallinity does not possess similar behavior as the data proves that all fitted parameters in this case might be consistent with zero. Our statistical result is then cross examined with the observations from X-ray diffraction (XRD) and Fourier Transform Infrared (FTIR) Spectroscopy, showing pretty good agreement. This result may indicate that the 10% NaOH pretreatment might not be sufficient in changing the crystallinity index of the sweet sorg...

Immobilization of Saccharomyces cerevisiae using Ca-alginate for bioethanol production from empty fruit bunch of oil palm

Immobilization of Saccharomyces cerevisiae using Ca-alginate bead was conducted to investigate the performance of S. cerevisiae in producing ethanol from empty fruit bunch of oil palm. Simultaneous saccharification and fermentation (SSF) and separated hydrolysis and fermentation (SHF) methods were used for both free cell and immobilized cell of S. cerevisiae. The result of SSF method for both immobilized and free cell of S. cerevisiae produced the highest ethanol concentration at 3.9% and 3.8%, respectively, after 48 hours fermentation. While the result of SHF method produced the highest ethanol concentration at 3.7% and 3.5%, respectively. Although ethanol concentration obtained with immobilized cell did not presented higher value as expected, it exhibited faster fermentation process, as at 24 hour fermentation, it converted higher ethanol concentration than the free cell.Immobilization of Saccharomyces cerevisiae using Ca-alginate bead was conducted to investigate the performance of S. cerevisiae in producing ethanol from empty fruit bunch of oil palm. Simultaneous saccharification and fermentation (SSF) and separated hydrolysis and fermentation (SHF) methods were used for both free cell and immobilized cell of S. cerevisiae. The result of SSF method for both immobilized and free cell of S. cerevisiae produced the highest ethanol concentration at 3.9% and 3.8%, respectively, after 48 hours fermentation. While the result of SHF method produced the highest ethanol concentration at 3.7% and 3.5%, respectively. Although ethanol concentration obtained with immobilized cell did not presented higher value as expected, it exhibited faster fermentation process, as at 24 hour fermentation, it converted higher ethanol concentration than the free cell.