Production of Bio-ethanol from Solid Waste Paper Using Biological Activation

Biomass energy is renewable energy source that comes from the material of plants and animals. Forms of biomass energy are bio-ethanol, bio methanol, and biodiesel. Bio-ethanol is one of the most important alternative energy sources that substitute the fossil fuels. The focus of this research is to produce bio-ethanol from waste office paper. Five laboratory experiments were conducted to produce bio-ethanol from wastepaper. The wastepaper was dried in oven and cut in to pieces. Then it passed through dilute acid hydrolysis, fermentation and distillation process respectively. High amount of ethanol was observed at 20 ml/g (liquid to solid ratio) and at the time of 2hr. Cost and economic analysis for ethanol production from wastepaper was performed. Results from the analysis indicated a paper to ethanol plant was feasible from the economic point of view with rate of return (RR) 38.61% and the payback period of 2.2 years.

The Kinetics Studies on Hydrolysis of Hemicellulose

The kinetics studies is of great importance for the understanding of the mechanism of hemicellulose pyrolysis and expanding the applications of hemicellulose. In the past years, rapid progress has been paid on the kinetics studies of hemicellulose hydrolysis. In this article, we first introduced the hydrolysis of hemicelluloses via various strategies such as autohydrolysis, dilute acid hydrolysis, catalytic hydrolysis, and enzymatic hydrolysis. Then, the history of kinetic models during hemicellulose hydrolysis was summarized. Special attention was paid to the oligosaccharides as intermediates or substrates, acid as catalyst, and thermogravimetric as analyzer method during the hemicellulose hydrolysis. Furthermore, the problems and suggestions of kinetic models during hemicellulose hydrolysis was provided. It expected that this article will favor the understanding of the mechanism of hemicellulose pyrolysis.

Biovalorization of Lignocellulosic Materials for Xylitol Production by the Yeast Komagataella pastoris

The main goal of this study was to screen different lignocellulosic materials for their ability to support the cell growth of the yeast Komagataella pastoris and the production of xylitol. Several lignocellulosic materials, namely banana peels, brewer’s spent grains (BSGs), corncobs, grape pomace, grape stalks, and sawdust, were subjected to dilute acid hydrolysis to obtain sugar rich solutions that were tested as feedstocks for the cultivation of K. pastoris. Although the culture was able to grow in all the tested hydrolysates, a higher biomass concentration was obtained for banana peels (15.18 ± 0.33 g/L) and grape stalks (14.58 ± 0.19 g/L), while the highest xylitol production (1.51 ± 0.07 g/L) was reached for the BSG hydrolysate with a xylitol yield of 0.66 ± 0.39 g/g. Cell growth and xylitol production from BSG were improved by detoxifying the hydrolysate using activated charcoal, resulting in a fourfold increase of the biomass production, while xylitol production was improved to 3.97 ± 0.10 g/L. Moreover, concomitant with arabinose consumption, arabitol synthesis was noticed, reaching a maximum concentration of 0.82 ± 0.05 g/L with a yield on arabinose of 0.60 ± 0.11 g/g. These results demonstrate the feasibility of using lignocellulosic waste, especially BSG, as feedstock for the cultivation of K. pastoris and the coproduction of xylitol and arabitol. Additionally, it demonstrates the use of K. pastoris as a suitable microorganism to integrate a zero-waste biorefinery, transforming lignocellulosic waste into two high-value specialty chemicals with high market demand.

Bioethanol production from Jatropha seed cake via dilute acid hydrolysis and fermentation by Saccharomyces cerevisiae

The interest in using Jatropha curcas L. as a feedstock for the production of bio-diesel is rapidly growing. Available literatures holds [promise for the simultaneous wasteland reclamation capability and oil yields of the plant hence fueling the Jatropha bio-ethanol hopes. This research investigated the bioconversion of cellulose from press cakes of Jatropha oil seeds, which is a byproduct from a biodiesel plant, into ethanol by using the methods of acid pretreatment, hydrolysis and fermentation by Saccharomyces cerevisiae. The process includes the pretreatment method of the finely ground cellulosic solid oilseed cake with dilute sulphuric acid and heating the mixture at a high temperature to break the crystalline structure of the lignocellulose to facilitate the hydrolysis of cellulosic component by dilute acids. About 63.33% ethanol was recovered as confirmed by the infra-red spectroscopy and the investigated physicochemical parameters show that the produced bioethanol holds promise for its use as a possible candidate for replacement for petroleum diesel.

Identification And Quantification Of Hydrocarbons Produced From The Acid-Pretreated Kitchen Waste By Using Fungal And Bacterial Strains

This study was conducted to identify and quantify hydrocarbons produced during bio-fuel production using kitchen waste (KW). KW is a complex mixture of hardly digestible compounds, mainly lignin, cellulose and hemicellulose, and easily digestible compounds, mostly starchy materials. Therefore, KW has a high potential for the production of biofuel after the chemical hydrolysis of lignocellulose, starch and carbohydrates. In this study, after the physically pretreatment (dried and crushed) of KW, dilute-acid hydrolysis was used for the hydrolysis of lignocellulose and starchy materials, eliminating the enzymes requirement. The dilute acid hydrolysis was conducted with 1, 3 and 5% (w/w) sulfuric acid at 90 and 120°C for 30, 60, 90 and 120 min. The hydrolysis with 5% acid at 120°C for 120 min resulted in the hydrolysate with the highest reducing sugar concentration of 97.917 ± 0.5 g/kg and Energy of 1.567 ± 0.008 MJ/kg. The reducing sugars were used as substrate in fermentation by fungal strain Aspergillus niger, bacterial strains Lacto-bacillus and Escherichia coli, to produce hydrocarbons. The fermented product was quantified after every day till the fermentation time is over i.e. no more products were formed. Biofuel production from Aspergillus niger, Escherichia coli and Lacto-bacillus was 64%, 45% and 50% after 72 hr. Fermented product contains mainly hydrocarbons as identified by GC-MS analysis. Calorific value of sample and biofuel determined on Differential Scanning Calorimetry were 0.6MJ kg− 1 for sample before fermentation and 3.56 MJ kg− 1, 3.33 MJ kg− 1 and 2.67 MJ kg− 1 for KW fermented by Aspergillus niger, Escherichia coli and Lacto-bacillus, respectively. Hence, maximum of 64% reducing sugars were converted into hydrocarbons (biofuel) after fermentation by Aspergillus niger.

Obtaining Fermentable Sugars from a Highly Productive Elm Clone Using Different Pretreatments

The interest of supplying lignocellulosic materials for producing fermentable sugars has recently emerged in order to diminish the negative environmental effects of fossil fuels. In this study, the Ulmus minor clone Ademuz, characterized for its tolerance to Dutch elm disease and its rapid growth, was evaluated as a source of fermentable sugars. For that, different pretreatments, comprising autohydrolysis, dilute acid hydrolysis, acid catalyzed organosolv, and alkaline extraction, were evaluated at two levels of severity (pretreatment temperatures at 160 °C and 180 °C, except for alkaline extraction at 80 °C and 160 °C); and the resulting pretreated materials were enzymatically hydrolyzed for fermentable sugars production. The major extraction of lignin and hemicellulose was achieved during organosolv (48.9%, lignin; 77.9%, hemicellulose) and acid hydrolysis (39.2%, lignin; 95.0%, hemicellulose) at 180 °C, resulting in the major enzymatic digestibility (67.7%, organosolv; 53.5% acid hydrolysis). Contrarily, under the most favorable conditions for autohydrolysis (180 °C) and alkaline extraction (160 °C), lower extraction of lignin and hemicellulose was produced (4.8%, lignin; 67.2%, hemicellulose, autohydrolysis; 22.6%, lignin; 33.1%, hemicellulose, alkaline extraction), leading to lower enzymatic digestibility (32.1%, autohydrolysis; 39.2%, alkaline extraction). Taking into account the sugars produced during enzymatic hydrolysis of pretreated materials and the solubilized sugars from pretreatment liquors, the highest sugars (glucose and xylose) yield production (28.1%) per gram of biomass from U. minor clone Ademuz was achieved with acid catalyzed organosolv at 180 °C.

Xylose Release From Sunflower Stalk by Coupling Autohydrolysis and Enzymatic Post-Hydrolysis

The purpose of this study was to obtain xylose-based fermentation media from autohydrolysis liquors of sunflower stalk by using commercial xylanase formulation. Xylose is generally produced from xylan by diluted acid hydrolysis that causes the formation of some unwanted compounds during the process. As an alternative to dilute acid hydrolysis method, enzymatic hydrolysis of xylan can provide more specific hydrolysis under moderate conditions and does not cause the formation of undesirable compounds. In this study, xylose production carried out with Trichoderma longibrachiatum xylanase on solubilized xylan form of sunflower stalk, which was hydrothermally pretreated for 1 hour at 160ºC. The effects of substrate concentration and enzyme activity were investigated for the production of xylose. To obtain a high xylose yield and selectivity, the optimization study was conducted by the response surface methodology. The optimum substrate concentration and enzyme activity were found as 60 mg ds/mL CAL and 234 U/mL, respectively. Under the optimum condition, xylose yield and selectivity were found to be 69.5% and 8.2 g/g, respectively. This study showed that xylose could be produce with a high yield without requiring a neutralization process and corrosive chemical reagent apart from water.

Bioethanol Production from Stalk Residues of Chiquere and Gebabe Varieties of Sweet Sorghum

Bioethanol produced from renewable resource has potential to solve environmental pollution and to satisfy the need of demand and supply. It favours the use of nonfood lignocellulosic materials. Ethanol produced from plant materials can sustain the economy by reducing cost of imported petroleum, emitting neutral CO2. Moreover, it enhances the economy by providing value added market opportunities for transportation and agricultural sector. Therefore, the objective of the study was to investigate bioethanol production from stalk residues of Chiquere and Gebabe varieties of sweet sorghum collected from West Arsi Zone, Ethiopia. Response surface methods with a three factor (inoculum size, pH, and dilution rate) with triplicate run by using the Box–Behnken method was referred. The experiment employed dilute acid hydrolysis, because it is an easy and productive process by treating the stalks with 4% of sulfuric acid for effective hydrolysis of substrate. Finally, the fermentation was carried out at 30°C for 72 hours on a shaker at 180 rpm by using Saccharomyces cerevisiae. The significance of the result was evaluated by using ANOVA, where P values <0.05 were considered statistically significant. In the process, maximum yield of ethanol was obtained at an inoculum size of 5% (22.40%), pH level of 4.0 (21%), and dilution rate at 10 ml (21.46%). Very low yeast inoculum size and dilution factor have positive effect on the yield of ethanol, whereas very high dilution rate produced negative impact on ethanol production. FTIR spectroscopy peaks associated with O-H, C-O, and C-H stretching vibrations confirmed the presence of ethanol obtained from sweet sorghum stalks. The results of our study indicated that, being available in bulky amounts and nonedible material, sweet sorghum stalks can serve as potential feedstock for bioethanol production in developing countries such as Ethiopia.