Anaerobic digestion is the natural breakdown of organic materials into methane and carbon dioxide gas and fertiliser. This takes place naturally, or in an anaerobic digester.
Biomass is a scientific term that’s used to describe energy derived from plant-derived materials. The primary component of woody materials, plant residues and grasses is called lignocellulose. The structure of the cell wall of lignocellulose is made of long chain sugars which can be turned into biofuels. These long chain sugars are converted to biofuels by introducing acids or enzymes, according to the United States Department of Energy. The definition of biochemical conversion is using living organisms or their products to convert organic material into fuel, according to Mondofacto.com.
Anaerobic Digestion - Anaerobic digestion is one of the natural processes used in biochemical conversion and is when microorganisms break down plant materials in the absence of oxygen. The process of anaerobic digestion usually results in a biogas composed of methane and carbondioxide, according to BioSystem Solutions. The three primary steps involved in anaerobic digestion are liquefaction, acid production and the production of biogas. Each step requires the use of a different type of anaerobic bacteria. One of the primary problems with anaerobic digestion for energy production is that biogas is difficult and expensive to store in a warehouse. However, biogas can be turned directly into heat or burned to produce electricity, according to Cal Recycle.
Fermentation - Fermentation is another one of the natural processes used in biochemical conversion. Fermentation involves genetically engineering bacteria so that when they are fed lignocellulose simple sugars, they convert sugars into a diesel-like gasoline, according to the United States Department of Energy. Enzymes primers are used in this process, which help increase the speed of fermentation. Fermentation of crops such as corn and sugar are currently used on a commercial level, but fermentation is not being used for cellulosic biomass because of higher production costs, according to Cal Recycle.
Composting - Composting is another type of natural process used in biochemical conversion and is also referred to as aerobic digestion, according to Cal Recycle. Animal manure is commonly used in composting and is a long process that usually takes a year or more to complete. Bacteria helps convert animal manure into biogas, which can then be used as fuel. The primary benefit of composting is that it helps to eliminate waste.
Transesterification - Transesterification is a process in which vegetable oils are converted into biodiesel, according to the University of Strathclyde. Some of the crops used to produce biodiesel include palm, soybean and rapeseed. The primary benefit of transesterification is that it is carbon-neutral. This means the crops absorb the same amount of carbon dioxide from the atmosphere while they are growing as they release when they are burned as biofuels.
Considerations - The cost of converting lignocellulose sugars into biofuels is currently too high to be considered as a viable alternative energy source, according to the United States Department of Energy. However, research is being conducted to try and reduce this cost. The goal of biochemical conversion research is to try and reduce processing costs, capital costs and to convert cellulosic biomass into sugars that can be fermented.