Determinacion De Acido Scorbico Por Titulacion

Biotechnology and Bioprocess Engineering 17: 316-325 (2012) DOI 10.1007/s12257-011-0472-1

RESEARCH PAPER

Production of Bioethanol from Sugarcane Bagasse Using NH4OH-H2O2 Pretreatment and Simultaneous Saccharification and Co-fermentation
Zhi-Sheng Zhu, Ming-Jun Zhu, Wan-Xia Xu, and Lei Liang

Received: 26 September 2011 / Revised: 13 December 2011 / Accepted: 21 December 2011 © The KoreanSociety for Biotechnology and Bioengineering and Springer 2012

Abstract In this study, we investigated the production of bioethanol from sugarcane bagasse (SCB) using an NH4OH-H2O2 pretreatment and simultaneous saccharification and co-fermentation (SScF). Response surface methodology and a 23 Box-Behnken design were used to evaluate the effect of different liquid mixture concentrations,liquid-tosolid ratios (LSRs) and pretreatment temperatures on the production of ethanol. The liquid mixture concentration and LSR significantly influenced the fermentation efficiency. Based on ridge max analysis, the following pretreatment conditions resulted in a fermentation efficiency of 95.79 ± 0.01%: liquid mixture concentration 53%, LSR 28, and a temperature of 63°C. A morphological analysisperformed using scanning electron microscopy (SEM) and chemical characterization revealed that these pretreatment conditions were effective in disrupting the sugarcane fibers and removing lignin. Ethanol fermentation with the pretreated SCB using SScF in yeast SHY 07-1 resulted in an ethanol concentration of 14.65 ± 0.17 g/L, an ethanol yield of 0.48 ± 0.01 g/g, and an ethanol productivity of 0.12 ±0.01 g/(L/ h), which represents increases of 106.02, 89.98, and 107.02%, respectively, over the values obtained from SScF with untreated SCB. Keywords: sugarcane bagasse, NH4OH-H2O2 pretreatment, response surface methodology, simultaneous saccharification and co-fermentation, ethanol fermentation
Zhi-Sheng Zhu, Ming-Jun Zhu*, Wan-Xia Xu School of Bioscience and Bioengineering, South ChinaUniversity of Technology, Guangzhou Higher Education Mega Center, Guangzhou 510006, China Tel: +86-20-3938-0623; Fax: +86-20-3938-0601 E-mail: mjzhu@scut.edu.cn Lei Liang Guangzhou Sugarcane Industry Research Institute, Guangzhou 510-316, China

1. Introduction
The depletion of fossil fuels has led to an increasing interest in the use of renewable resources, for example, agricultural waste for theproduction of alternative fuels such as bioethanol [1,2]. However, it is not sustainable to produce bioethanol from grains such as corn and wheat in several countries, including China [3,4]. Lignocellulosic materials are attractive feedstocks for the production of bioethanol because they are abundant and cheap. One of the major lignocellulosic materials considered for bioethanol production in tropicalcountries is sugarcane bagasse (SCB), which comprises the fibrous residue that remains after extracting the juice, mainly sucrose, from sugarcane in the sugar production process. More than 70% of SCB consists of hydrolyzable carbohydrates that can yield fermentable sugars for the production of value-added bio-products [57]. It is estimated that each year approximately 100 million dry tons of SCBare produced around the world. Although most SCB is burned to produce steam power, there is still a surplus of this material leftover that can be used for bioethanol production [8]. To overcome the innate recalcitrance of the biomass and to effectively convert lignocellulosic feedstocks to fermentable sugars via enzymatic hydrolysis, the raw biomass should be pretreated. Several pretreatmentmethods exist, depending on the type and composition of biomass, which include different types of chemical, physical and physicochemical techniques [1,4,6]. Regardless of the exact method used, the goal of pretreatment is to alter or remove lignin and/or hemicellulose, disrupt the crystallinity of cellulose, and increase porosity so that the cellulose becomes more accessible to cellulase enzymes...