Bioethanol is a principle fuel that is normally used as a petrol substitute for the vehicles. This fuel is produced during the sugar fermentation process but also can be produced through the chemical process of reacting steam with ethylene. Most of the time, the sources of sugar that are needed for the production of ethanol normally come from energy crops or fuel which include crops like corn, wheat crops, maize, wheat crops, willow, sawdust, waste straw, reed canary grass, Jerusalem artichoke, cord grasses, some popular trees amongst other plants and energy sources.

The bioethanol can be produced from biomass through the fermentation process or hydrolysis. The biomass wastes are normally known for the complex compositions of the carbohydrate polymers that are normally gotten from the plant cell wall which are referred to as cellulose, lignin and hemi cellulose. The whole procedure involves the extraction of sugars from the biomass which is pretreated with enzymes or acids so as to reduce the feedstock size and open up the plant's structure. There are normally three major ways of extracting sugar from the biomass which are:

The Concentrated Acid Hydrolysis Process

It involves adding 70-77% of sulphuric acid to the biomass which is already dried to a 10% moisture content. In this process the acid is added in a ratio of 1.25 acid to 1 biomass which has a temperature that is controlled to a 50°C. After this, water is added to dilute the sulphuric acid to 20 - 30 % and the mixture is heated to a 100°C for an hour. Then the gel produced from the mixture is pressed to produce an acid sugar mixture and using the chromatographic column the sugar mixture is used to separate the acid.

Dilute Acid Hydrolysis

This is where a dilute acid is used to hydrolyze the biomass into sucrose. During the first stage you will use 0.7% of the sulphuric acid at 190°C in order to hydrolyze the present hemi cellulose in the biomass. Then during the second stage the process is optimized so as to yield a more resistant cellulose fraction which is accomplished by using 0.4% of the acid at 215°C. Then the liquid hydrolates are neutralized which are then recovered from the process.

Enzymatic Hydrolysis

This involves the use of enzymes to break down the biomass but using similar procedures used to hydrolyze the biomass into sucrose through the use of acids. It is important to note that this is one of the most expensive processes even in the very early stages of the development.

There are basic processes and different stages for the bioethanol from biomass.

Some of the procedures involve the following steps:

• Handling biomass: This is where the biomass undergoes a size-reduction stage which will make it much easier to handle as well as make the whole process for ethanol production more efficient.
• Pretreatment of the Biomass: This is where the hemi cellulose fraction of the biomass is broken into simple sugars. The hydrolysis occurs when the dilute sulphuric acid is mixed with biomass feedstock whereby the hemi cellulose complex sugars are broken down into simple sugars. The hemi cellulose sugar undergoes a conversion of the sugars into five carbon sugars which are xylose and arabinose followed by six-carbon soluble sugars which are mannose and galactose.
• Enzyme Production: This is where the cellulose enzymes are grown, which are normally used to hydrolyze the biomass cellulose fraction. Still one has the option of purchasing the enzyme from the enzyme companies.
• Cellulose Hydrolysis: This is where the remaining cellulose is hydrolyzed to glucose.
• Glucose fermentation: This is where the glucose is converted into ethanol through the help of bacterial or yeast which are useful for feeding on the sugars.