**3. Concluding remark**

Over the past four decades, the data show three distinct periods of food price inflation, and the lowest of which was during 1991–2015 at 2.6%, encompassing the biofuel boom. Comparatively, the inflation rate during 1981–1991 was 3.8%, and the rate during 1973–1981 was 8.3%. There was no noticeable change in the world's average grain and oil price inflation before and after 2000, in reference to the beginning of the biofuel boom. Crude oil prices, however, have had the highest correlation with food price indices. Currently, the main barriers to the spread of biofuel are its relevant cost of production and competition between some types of biofuels and food stock. Therefore, wastes play an important role in reducing these costs and recycling dump materials. Production of biofuels from nonfood biomass has emerged as a sustainable option to tackle the problems associated with growing demand of energy.

In this work, as well as providing the descriptions on emerging biofuel technologies to mimic the above-mentioned risks, the chemical and thermal properties of biofuels are described. For example, methanol and ethanol are studied as possible alternative liquid fuel candidates to resemble several physical and combustion properties of gasoline. The study shows that such a fuel blend decreases the engine brake power, increases the BSFC, and decreases the CO and HC emissions, compared to those produced using gasoline (fossil) fuel. The pretreated samples are analyzed for mass and energy yields, calorific values, proximate and elemental compositions, and thermal decompositions. This book also provides basic analyses of diesel, gasoline, and various types of biofuels (including biodiesel fuels) and assessment on limited and unlimited emissions (e.g., greenhouse gases, dangerous exhaust gases, and strong carcinogens and their contents) during and after combustion pathways. The results are evaluated in comparison to trusted measurements and numerical standards. The research equipment is

A one-dimensional model of gasoline engine is developed for predicting the effect of various fuel types on engine performance, specific fuel consumption, and emissions. The role of microbial consortium-based biocatalyst strategies that are being developed to address these issues are reviewed and discussed. Microbial co-culture biocatalysts are engineered to specialize the conversion of a general class of substrates present in the biomass hydrolysates into biofuel intermediates, with the capability of adapting them to the variable composition of the feedstock. The techniques being developed to understand the interaction between the members of the bioconversion consortia and the corresponding population dynamics of the engineered co-cultures are also presented. The simulation of transesterification requires in-depth understanding of the chemical reactions that take place inside the reactor. The development of reaction mechanism of the multiple step triglyceride, triglycerides, and monoglycerides and their reversal reaction is beyond the interest of chemical or mechanical engineers, whose main interests focus on the assessment of the overall conversion and the established performance process metrics. The work undertakes all relevant activities by establishing and formulating the overall process kinetics, as far as the rate constant and activation energy. The obtained values are used to carry out high fidelity reactive flow of the multiple

adapted with sensitivity measurements to the environmental contamination.

**2. Contribution of this book**

4 Biofuels - Challenges and opportunities

To conclude, the use of biofuels is expected to contribute to the energy sustainability and reduction of global warming. For instance, many efforts have been made to replace gasoline and diesel fuels with ethanol/gasoline and biodiesel/diesel fuel blends, respectively [11–16]. These efforts have been driven mainly by the importance of reducing greenhouse emissions and fossil fuel costs [17–19]. According to the US environment protection agency [20], all gasoline engine vehicles can use a blend of gasoline fuel with up to 10% volume fraction of ethanol without the need for engine modification. The reduction in CO<sup>2</sup> emissions without the loss of engine performance is nontrivial for this mixture [21]. For example, mixtures with up to 15% volume fraction of ethanol and 85% volume fraction of gasoline fuel have been approved for use in 2001 and newer vehicles, under the US federal standards for renewable fuel [22]; while mixtures with up to 85% volume fraction of ethanol and 15% volume fraction of gasoline fuel (i.e., flex fuels) have been defined as qualifying alternative fuels for flex-fuel vehicles [20]. Therefore, it was important to investigate the difference between ethanol and gasoline fuel characteristics and their blends.
