As biofuel is the fuel which directly derived from biomass, biodiesel needs a special process to transform its source from the biomass to a fuel.

Let see what the definition of both that I excerpt from various sources from the internet:

Biodiesel

1. Palm Biodiesel is an alternative fuel derived from palm oil and can be used in compression ignition engines i.e. diesel engines without any modifications. It refers to methyl esters derived from palm oil through a process known as ‘transesterification’. Source: Carotino

2. Biodiesel, however, is an alternative fuel to petroleum-based diesel, which can be manufactured from vegetable oils such as palm, rapeseed (canola), soy, linseed, jatropha and coconut oil. Biodiesel can also be manufactured from animal fats (including tallow) and used cooking oils.

The use of Biodiesel does not require any major changes in the fuel distribution system, avoiding the need for expensive additional infrastructure.

In many instances, Biodiesel is mixed with petroleum-based diesel to create a Biodiesel blend, which can then be sold into the general diesel market. Source: Mission Biofuels

Biofuel:

1.Biofuel is any fuel that derives from biomass — recently living organisms or their metabolic byproducts, such as manure from cows. It is a renewable energy source, unlike other natural resources such as petroleum, coal and nuclear fuels. A better definition of Biofuel is any fuel with an 80% minimum content by volume of materials derived from living organisms harvested within the ten years preceding its manufacture.[citation needed] Agricultural products specifically grown for use as biofuels include corn and soybeans, primarily in the United States, as well as flaxseed and rapeseed, primarily in Europe.

Much research is currently in progress into the utilization of microalgae as an energy source, with applications being developed for biodiesel, ethanol, methanol, methane, and even hydrogen. On the rise is use of hemp, although current politics currently restrains it. Waste from industry, agriculture, forestry, and households can also be used to produce bioenergy; examples include straw, lumber, manure, sewage, garbage and food leftovers.

Most biofuel is burned to release its stored chemical energy. The largest advantage of biofuel in comparison to most other fuel types is that the energy within the biomass can be stored for an indefinite time-period and without any danger. Source: Wikipedia

Both of biodiesel and biofuel posses their own advantages as well as disadvantages.

While biofuel can be directly derived from any vegetable oil and needs no any chemical process to allow it to flow in any diesel engine, the biodiesel fuel are mostly consist of vegetable oil mixed with the diesel and some chemical subtances.

The use of Biofuel however require minor changes in the fuel distribution system adding some components such as fuel filters,heater, changing valves and extra oil tanks.

In the opposite side, the benefits of Biodiesel are:

a. Biodiesel produces approximately 80% less carbon dioxide, and almost 100% less sulphur dioxide;

b. Biodiesel, when used as an additive, improves the lubricity of ultra low sulphur diesel. In the next articles we will discuss the properties and qualities of both oils.