Branched-Chain Higher Alcohols - Biotechnology in China: Biofuels and Bioenergy - page 104

In China, biofuels developed from biomass are playing more and more essential
roles in the national energy structure [ 8 ]. In 2010, the total biofuel production in
China was 1.58 million tons, including 1.52 million tons of fuel ethanol and 0.3
million tons of biodiesel, which were produced mainly from grains and recycling
cooking oils [ 9 , 10 ]. With limited arable land per capita, this path to biofuel
development risks the security of grain supply in China. Despite these obstacles,
the Chinese government still sees potential benefits from biofuels, provided that
they are produced commercially from nonfood feedstocks, and put in place a
national goal of increasing their share in fuel consumption to 15% by 2020 from
only 2% presently. In addition, the government has also pledged as part of the
Copenhagen agreements to cut carbon emissions by 40-45% per unit GDP pro-
duction compared with the 2005 level. This commitment translates into an
investment of at least 1% of GDP (CNY 240 billion) in China's clean energy
sector in the next 5 years. Except bioethanol and biodesiel, developing higher
alcohols as biofuels is one of most important parts of the long-term plan of China's
clean energy [ 11 , 12 ].
China has the second largest market for chemicals in the world after the USA [ 13 ].
The robust Chinese economy is stimulating the growth of the chemical industry,
even though the world is still suffering from an economic recession. In 2007, China
recorded a GDP growth rate of 11.4%, but the chemical industry grew at a rate of
26% during the same year. It is projected that the consumption of power parity of
China will surpass that of the USA within the next 10 years, and this will emerge as a
driving force for domestic producers, and is encouraged by the government as a
solution to alleviate its dependence on exports for trade balances with the West. This
also indicates opportunities for the use of chemicals such as higher alcohols.
Presently, great efforts are being made for bioethanol production in China [ 14 ].
However, unfortunately, BCHAs, such as isopropanol, isobutanol, 3-methyl-1-
butanol, and 2-methyl-1-butanol, have been produced from a renewable source
with lower yields, not high enough to make them viable as a gasoline substitute,
not only in China but also worldwide. Developing BCHAs is still an extremely
challenging path to be explored. We summarize here the current status of pro-
duction and consumption of the main BCHAs and some preliminary progress and
the possibility of developing microbial production of BCHAs in China, especially
with the combination of metabolic engineering and synthetic biology.
2 Market Consumption and Supply of BCHAs in China
2.1 Fuel Market Analysis
As in the international market, there are two primary uses for BCHAs in China,
either as base chemicals or as high-energy, low-emission fuel oxygenates [ 15 ].
For base chemicals, BCHAs are used as feedstocks for manufacturing many