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Termites are by far the oldest social insects in the world (in the cluster of living insects, the coordination and internal differentiation of their clusters are significant), and the survival history has been as long as 250 million years. So far, more than 2,600 species of termites have been found all over the world and distributed throughout the world. Their distribution area accounts for about 50% of the global land area. At present, there are more than 470 species of termites recorded in China, except Heilongjiang, Jilin, Qinghai, and Inner Mongolia, Ningxia and Xinjiang autonomous regions. The damage of termites to buildings, especially brick and wood structures, and wooden structures often leads to the sudden collapse of houses and even the consequences of casualties.
However, do you know that "notorious" termites are both destroyers and builders? More than 90% of the termite species do not pose a hazard to humans. Most of these species are found in tropical and subtropical forests and grasslands. They play an important role in accelerating the decomposition of Organic matter on the surface, promoting material circulation, purifying the surface, and increasing soil fertility. Even more worthy of our attention is the use of termites in bioenergy.
Termite to ethanol
In today's energy shortage, bioenergy has drawn attention from all parties. Today, ethanol is regarded as the best alternative fuel for oil and Other energy sources, and its efficient conversion technology and clean utilization are increasingly receiving worldwide attention.
In nature, lignocellulose is the most important form of living storage for solar energy and it is the most abundant renewable resource on the planet. According to statistics, annual photosynthesis on the earth can produce more than 100 billion tons of plant dry matter, of which more than half are cellulose and hemicellulose. In addition, waste generated from human activities such as agricultural waste (straw, rice hulls, wheat straw, peanut hulls, corn cobs, cottonseed hulls, bagasse, etc.), food processing wastes (peels, pomace, etc.), wood wastes (wood shavings, Bark) and municipal waste also contain a lot of cellulose. The total annual production of lignocellulosic biological resources in China is about 1.392 billion tons, which is too wasteful if it is not used. Our country currently consumes about 80 million tons of fuel each year. We only need to convert half of the lignocellulosic biomass that we produce each year into ethanol, and the quantity can exceed two times the total gasoline consumption in China.
But how to make ethanol? Western countries are trying to use corn, wheat, sugar and other foods to make ethanol to meet the growing energy demand. Researchers from the Guangdong Provincial Insect Research Institute turned their attention to termites. According to researcher Zhong Junhong, the person in charge of the project, “With current technology, replacing gasoline with alcohol is very easy. The key is how do you produce more? Alcohol, also known as ethanol, uses termites to achieve this goal."
Termites have intestinal tracts
How to do it?
Termite's stomach itself is a small processing plant that can eat and digest cellulose to convert it into energy. Zhong Junhong and others plan to use it to digest the function of cellulase and clone the gene and mass produce it. New energy development.
Like ours, termites eat lignocellulose in their stomachs and digest them and convert them to glucose. The difference is that cellulose in human diets is mainly contained in vegetables and rough-processed cereals and cannot be digested and absorbed, but termites Can do this.
Zhong Junhong said that the efficiency of directly degrading cellulose with cellulase is not high, and lignocellulose is usually covered with lignin, which is difficult to degrade, making cellulase poor in accessibility to cellulose, and the enzyme does not function properly. The low conversion efficiency causes significant obstacles to the utilization of lignocellulose. Termites can first decompose lignin and then use enzymes to digest the cellulose, which increases the efficiency considerably.
Termites, which mainly use cellulose as food, play an important role in the bio-circulation of lignocellulose, especially in tropical regions, becoming an important degrader of lignocellulose. In some tropical arid regions, cultivated termites consume more than 90% of dry wood; in relatively humid savanna they can mineralize 20% of primary biomass. During the long-term evolution of termite special diets, intestinal commensal microbial communities capable of efficiently degrading cellulose have been established in the digestive system. The self-produced cellulase has closely cooperated with the cellulase from the microorganism and is highly adaptable. Its corresponding digestive system. Termite's intestinal system's ability to digest plant cell wall polysaccharides is 30% to 40% higher than that of large herbivore's rumen microorganisms. It can be considered as a small-scale bioreactor—by a grinder (ie, It is composed of jaws and forefoot called chewing tissue, reaction pool (digestive tract), enzymes and microflora.
Clone termite cellulase
The ultimate goal of the experts is to clone.
Experts found that the good cellulase in nature is found in the termites. Therefore, it is hoped that it will be cloned into microorganisms, and then the microorganisms will be used to produce a large amount of cellulase, which will then digest the cellulose. Clone technology is now very successful, as long as the termite can efficiently digest cellulase gene fragments to find out, and then put the gene in another engineering bacteria, you can turn the natural cellulose into monosaccharides, and then the monosaccharide Fermented and turned into alcohol.
Finding a better termite species is the key. Having a good termite intestinal cellulase gene, the utility of cloning it is high. Now experts from the Guangdong Provincial Institute are still selecting species rich in cellulase termites. Four or five species have been selected.
Many people think that this project has great prospects. Guangdong is located in the South and South Tropics. Termite resources are abundant. It is one of the provinces with the most distributed termites in China, second only to Yunnan. According to incomplete statistics, there are 71 species of termites in Guangdong Province. These highly termites are termites in China. Intestinal cellulase gene rich resources. You know, Americans have to go to Africa to collect termites for this project. (Tan Ping Ding Xuejie)
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