1. Introduction
Alternative fuels for internal combustion engines have recently
attracted considerable attention due to the ever diminishing petroleum
reserves and environmental consequences of increasing
greenhouse gas emissions. The growing environmental concerns,
tougher Clean Air Act Standards [1,2] and Renewable Fuel Standard
(RFS) Mandates [3] are among the major drivers for development
of alternative fuels from renewable resources that are sustainable
and environmentally acceptable. The U.S. RFS sets a goal of 36 billion
gallons of biofuels production by year 2022, of which 21 billion
gallons should come from the so-called ‘‘advanced biofuels’’
and a minimum of 1 billion gallons of biodiesel.