Laszlo Kotai, Janos Szepvolgyi, Maria Szilagyi, Li Zhibin, Chen Baiquan, Vinita Sharma and Pradeep K. Sharma

Additional information is available at the end of the chapter http://dx. doi. org/10.5772/52379

1. Introduction

Biobutanol (n-C4H9OH, available as fermentation product of various carbohydrate derivatives obtained from different resources of agricultural production such as crops and wastes) is one of the most promising biofuels in the near future. It can be produced by the so-called ABE (acetone-butanol-ethanol) type anaerobic fermentation discovered by Pasteur [1, 2] and industrialized by Weizmann [3]. Main problems associated with industrial production of biobutanol include high energy demand for processing of dilute ferment liquors and high volume of wastewater. A bioreactor with a volume of 100 m3 produces at 90% filling ratio 1053 kg of butanol, 526 kg of acetone and 175 kg of ethanol together with 2900 kg of carbon dioxide, 117 kg of hydrogen and 84150 kg of wastewater. Efforts to increase productivity and decrease production costs resulted in many new methods. This chapter summarizes some selected results on methods of biobutanol production.

2. History of industrial biobutanol production

During investigations aimed at discovering cheaper sources of acetone and butanol for chemical industry, Weizmann [3] isolated an organism which could ferment a fairly concen­trated corn mash with good yields of acetone and butanol. In 1915 the British Admirality took over the research and carried out large-scale tests in an improvised apparatus but without

providing proper conditions for laboratory testing. Thus the experiment failed due to lack of strict sterility throughout the system. Later on, British Acetones Ltd. undertook the initiation to duplicate laboratory bacteriological conditions on a commercial scale using corn meal. Butanol and acetone were produced from April 1916 to November 1919 in a total of 3458 runs of 24,000 gals of mash each. There was no run unfit for distillation [4]. By modifying the raw materials and technological conditions an explosion-like development of acetone-butanol fermentation technologies took place. Beesch [5] collected the available knowledge about industrial acetone-butanol fermentation process details, including usability of raw materials, problems of contaminations, infections, treatment of the by-products and recovering the end — products. During World War II the ABE fermentation became the most voluminous industrial biochemical process. However, the cheap petrochemical-based butanol production withdrawn it almost completely in the USA and Europe later on. In China, however, the ABE fermentation industry started only in the early 1950s in Shanghai and expanded rapidly thereafter. At its peak, there were about 30 plants all over the country and the total annual production of solvents reached 170,000 tons [6]. The success of the ABE industry in China had special features like development of continuous fermentation technologies such as in Russia, where the AB plants were the only full-scale industrial plants which used hydrolyzates of lignocellosic wastes for butanol fermentation and the process was finally run in a continual mode [7]. In China, the main strategic considerations were as follows: maintaining maximal growth and acid production phase, adoption of multiple stages in the solvent phase to allow gradual adaptation to increasing solvent, and incorporation of stillage to offer enough nutrients to delay cell degeneration. A biorefinery concept for the use of all byproducts has been elaborated and was partially put into practice. Due to the tremendous national demand for solvents, China has begun a new round of ABE fermentation research. It is expected that a new era in the ABE industry is on the horizon [6].