Study of Enzymatic Hydrolysis of Dilute Acid Pretreated Coconut Husk

Coconut husk is classified as complex lignocellulosic material that contains cellulose, hemicellulose, lignin, and some other extractive compounds. Cellulose from coconut husk can be used as fermentation substrate after enzymatic hydrolysis. In contrary, lignin content from the coconut husk will act as an inhibitor in this hydrolysis process. Therefore, a pretreatment process is needed to enhance the hydrolysis of cellulose. In this study, the pretreatment was done using dilute sulfuric acid in an autoclave reactor. The pretreatment condition were varied at 80°C, 100°C, 120°C and 0.9%, 1.2%, 1.5% for temperature and acid concentration respectively. The acid pretreated coconut husk was then hydrolyzed using commercial cellulase (celluclast) and β-glucosidase (Novozyme 188). The hydrolysis time is 72 hours and the operating conditions were varied at several temperature and pH. The highest sugar concentration (1.128 g/L) was obtained at pH 4 and 50°C which is pretreated at 100°C using 1.5% acid concentration

A Study of the Use of Borates in Semi-Chemical Pulping

The purpose of this project was to identify sodium metaborate as a pulping chemical in semi-chemical pulping with soda ash. The experimental design included four digester cooks with 0%, 10%, 20%, and 40% addition of.the borate compound. The resulting yields were 81. 3 %, 79. 2%, 77.4 %, and 7 4. 5% respectively. Therefore, under the definition of pulping, sodium metaborate was considered a pulping chemical. The pulps were mechanically refined. The resulting screened rejects increased with increasing borate addition. Handsheets were made and tested for strength and optical properties. The tensile and mull en strengths of the handsheets increased with addition of borates up to 20%, but degradation of the bonding properties occurred at high addition levels (40%). The tear strength increased dramatically (up to 24.1%) with the addition of borates to the pulping liquor. Brightness and visual color were slightly improved. The results indicate that the sodium metaborate was an effective pulping chemical with a tendency to be selective in delignification. Further work should be performed to compare the effect of substitution against conventional non-borate pulping, and possible changes in bleached pulp quality

Full Sequence Bleaching with Dimethyldioxirane

Research work to date has shown dimethyldioxirane to be a very powerful, yet highly selective oxidant. Dimethyldioxirane bleaching may become more important in the future with legislative restrictions on chlorine based bleaching agents as it contains no chlorine. Most work with dimethyldioxirane to date has concentrated on short sequence bleaching, or the use of peroxymonosulfate as a pre-treatment to improve oxygen delignification. The goal of this study was to develop a full sequence bleaching containing only dimethyldioxirane and other chlorine free bleaching agents that matched the brightness and strength characteristics of comparable chlorine dioxide based full sequences. Dimethyldioxirane was found to match the strength, but not the brightness of, chlorine dioxide. As well, dimethyldioxirane may be harsher on cellulose than chlorine dioxide. Additional optimization may allow dimethyldioxirane to perform as well as chlorine dioxide. It was seen that increased brightnesses were achieved by using optimum conditions and a step-wise chemical addition. As well, the addition of peroxide to dimethyldioxirane stages may increase brightness

Delignification by Using Alkaline-acid Pretreatment on Bioethanol Production From Rice Straw

Rice straw as agricultural waste contains cellulose that potentially to produce ethanol. However, it has lignin content that will inhibit the enzyme in converting glucose into ethanol. In this research, pretreatment steps aim to release and breakdown lignin in rice straw. Pretreatment was conducted in two phases, alkaline pretreatment using NaOH (1%,2%,3%,4%,and 5%) and acid pretreatment using 1% H2SO4 with various heating time (30, 60, 90, 120 and 150 minutes) and used for ethanol production by means of Simultaneous Saccharification and Fermentation (SSF) with cellulose enzyme and Saccharomyces Cerevisiae. The results showed that higher NaOH concentration using on alkaline pretreatment and longer heating time on acid pretreatment made morbe degraded lignin content. The highest ethanol content produced was 48.38% from delignification treatment with NaOH concentration of 5% and acid pretreatment time of 150 minutes

Pretreatment of Miscanthus giganteus with Lime and Oxidants for Biofuels

ACKNOWLEDEGMENTS The authors are grateful to the Energy Biosciences Institute, University of California, Berkeley, Berkeley, CA, for financial support, Dr. Stefan R. Bauer, Valerie D. Mitchell, and Ana Belen Ibanez Zamora for technical assistance, and Jason Cai for fruitful discussions. The authors thank the China Scholarship Council for financial assistance to Fuxin Yang during his stay at University of California, Berkeley.Peer reviewedPostprin

Second-generation bioethanol from industrial wood waste of South American species

There is a global interest in replacing fossil fuels with renewable sources of energy. The present review evaluates the significance of South-American wood industrial wastes for bioethanol production. Four countries have been chosen for this review, i.e., Argentina, Brazil, Chile, and Uruguay, based on their current or potential forestry industry. It should be noted that although Brazil has a global bioethanol market share of 25%, its production is mainly first-generation bioethanol from sugarcane. The situation in the other countries is even worse, in spite of the fact that they have regulatory frameworks in place already allowing the substitution of a percentage of gasoline by ethanol. Pines and eucalyptus are the usually forested plants in these countries, and their industrial wastes, as chips and sawdust, could serve as promising raw materials to produce second-generation bioethanol in the context of a forest biorefinery. The process to convert woody biomass involves three stages: pretreatment, enzymatic saccharification, and fermentation. The operational conditions of the pretreatment method used are generally defined according to the physical and chemical characteristics of the raw materials and subsequently determine the characteristics of the treated substrates. This article also reviews and discusses the available pretreatment technologies for eucalyptus and pines applicable to South-American industrial wood wastes, their enzymatic hydrolysis yields, and the feasibility of implementing such processes in the mentioned countries in the frame of a biorefinery.Fil: Vallejos, María Evangelina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Kruyeniski, Julia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; ArgentinaFil: Area, Maria Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Materiales de Misiones. Universidad Nacional de Misiones. Facultad de Ciencias Exactas Químicas y Naturales. Instituto de Materiales de Misiones; Argentin

Enzymatic Hydrolysis of Alkaline Pretreated Coconut Coir

The purpose of this research is to study the effect of concentration and temperature on the cellulose and lignin content, and the reducing sugars produced in the enzymatic hydrolysis of coconut coir. In this research, the coconut coir is pretreated using 3%, 7%, and 11% NaOH solution at 60oC, 80oC, and 100oC. The pretreated coir were assayed by measuring the amount of cellulose and lignin and then hydrolysed using Celluclast and Novozyme 188 under various temperature (30oC, 40oC, 50oC) and pH (3, 4, 5). The hydrolysis results were assayed for the reducing sugar content. The results showed that the alkaline delignification was effective to reduce lignin and to increase the cellulose content of the coir. The best delignification condition was observed at 11% NaOH solution and 100oC which removed 14,53% of lignin and increased the cellulose content up to 50,23%. The best condition of the enzymatic hydrolysis was obtained at 50oC and pH 4 which produced 7,57 gr/L reducing sugar