**2.1. Historical background**

In the abundance of biomass in the world's nature, traditional utilisation of biomass in order to survive has long been established. Primitively, when man knows how to create fire, biomass utilisation evolved from domestic usage to even larger application such as building houses, clothes production, paper making, etc. Yet the biomass utilisation seems endless and continues to produce more relevant products.

Henry Ford was the first to design a model car that runs using ethanol, and it was also reported that Rudolph Diesel intended on using vegetable oil to power his car engine [8]. However, at the time of World War II, fossil fuels were more practical based on supply, price and efficiency which caused biofuel to be unpopular. In contrast, in the late 1990s, high intensity of research and investment were made to produce biofuel from biomass due to reverse effect on supply and price of fossil fuel which is unpredictable.

The first biomass used was in solid form—wood—which was used to produce fire and oil derived from plants and animals that has been turned to a useful medium to light up lamp [9, 10]. In the present day, biofuel is derived from food crops like sugar beets, grains and vegetable oils or, namely, first-generation biomass [11]. However, the impact on the global food supply and sustainability of land led to non-food stock for energy sources and the second generation of energy sources such as cellulosic biomass, inedible oil and algae-derived oil [11, 12]. Microalgae can reproduce in a mass rapidly per day and have been found enriched of high level of oil in total dry biomass [13]. However, regardless the high growth rates or high oil content, algae-derived oil production faces challenges that needed attention such as strain isolation, nutrient sourcing or availability, on-site management in production and handling and residual biomass or waste management [14].

Meanwhile, biobutanol, another type of fuel, has becoming popular in recent years that surpass bioethanol. Biobutanol is referred as the next generation of biofuels that offers many advantages. It can be produced directly with few combinations of physical, chemical and biological processes from food crops such as cereal crops, sugar beets and sugar cane. The first synthesis of biobutanol was achieved during 1912–1914 by acetone-butanol-ethanol (ABE) fermentation using Clostridium species as catalysts [15].
