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Clean new energy is also known as green energy; its greatest feature is that it does not cause environmental pollution upon combustion or use, which helps to maintain ecological balance. Developing clean new energy is the direction for the growth of the energy industry in the future. Here, the achievements obtained in research on the application of biotechnology, particularly microbial technology, in the development of clean new energy are highlighted. I. Development of new types of fuel cells Fuel cells generate electricity through the direct reaction of gaseous fuels such as hydrogen and methane with oxygen; they are efficient and produce little pollution, making them a very promising approach for energy utilization. Traditional fuel cells use hydrogen as a fuel, but hydrogen is difficult to produce and store, which keeps the cost of fuel cells high. Researchers at the University of Pennsylvania in the United States have developed a new type of battery that uses hydrocarbons such as methane as fuel, and its cost is **lower than that of traditional fuel cells that use hydrogen. Researchers have tried using inexpensive hydrocarbon fuels, but the \"residues\" resulting from chemical reactions tend to accumulate on the nickel-based cathodes of the batteries, causing circuit breaks; using a mixture of copper and ceramics to make the battery cathodes resolved this issue of residue accumulation. The newly developed fuel cells can use five types of hydrocarbons, including methane, ethane, toluene, butylene, and butane, as fuel sources. Hydrocarbons such as methane can be produced through microbial fermentation, providing a rich and diverse source of raw materials for the development of new fuel cells. At present, the energy conversion efficiency of this new type of fuel cell is still low, and further research is needed to improve it. II. Development of dual-use bioenergy Whether it is military weapons such as most mobile equipment, or civilian vehicles and other modes of transport, they all use gasoline or diesel as fuel. It would be ideal to use hydrogen as a fuel, and its advantages include: (1) it is clean and does not pollute the environment ； (2) High thermal efficiency, about 3 times that of gasoline ； (3) Biological hydrogen production holds potential. For this very reason, making full use of biotechnology to produce hydrogen holds great potential. When Rhodopseudomonas sp. is used as the producing strain to generate hydrogen from starch, good results are achieved; 1 milliliter of hydrogen can be produced per gram of starch consumed. Hydrogen mixed with other small amounts of fuel can replace gasoline and diesel. Ethanol is also a clean biofuel with a wide range of applications, and can be used as a substitute for gasoline and diesel. In countries such as Japan and Canada, **\"engineered yeast\" created using genetic technology is used to produce ethanol by hydrolyzing cellulose, thanks to its high enzyme activity** ； There are also engineered E. coli strains that can effectively convert glucose into ethanol ； These types of ethanol can be used as a substitute for gasoline or diesel, providing an abundant supply of biofuel for motorized equipment at any time. In fact, organisms that can produce hydrogen and ethanol are not only bacteria or \"engineered bacteria\"; certain algae and other microorganisms also have the ability to produce hydrogen or ethanol. Researchers from the University of California in the United States and others have discovered that a green alga (eukaryote) called Chlamydomonas reinhadtii has the ability to produce large amounts of hydrogen continuously. The key is to control its growth environment by removing sulfur from the growth nutrient solution; under these conditions, the algae cease photosynthesis and stop producing oxygen ； Under anaerobic conditions, the algae must generate the energy required for adenylosuccinate triphosphate synthesis through other pathways, utilizing the stored energy to achieve their ultimate goal of producing hydrogen. Generally speaking, this natural algae produces very low amounts of hydrogen; therefore, on the one hand, it is necessary to control the factors that are essential for its growth or that hinder such growth ； On the other hand, molecular genetic techniques are used to modify the characteristics of algae in order to enhance their hydrogen production capacity. It is evident, therefore, that there is potential in making full use of various organisms to develop clean bioenergy for both military and civilian purposes. III. Microalgae represent the cheapest way to obtain hydrogen energy. As mentioned earlier, green algae and microorganisms can be used to produce hydrogen; here, the potential of microalgae for hydrogen production is emphasized. Scientists predict that when oil and natural gas run out, hydrogen could serve as a relatively ideal energy source. The key is to find a cheap method for producing hydrogen. Some experts believe that utilizing the hydrogen-producing ability of green algae in ordinary ponds might be the most practical option—economic, practical, and widely available. Green algae, these tiny lower plants, reproduce rapidly and are found all over the world. They have the ability to produce hydrogen in the presence of water and sunlight. Under artificial control, green algae can be forced to produce hydrogen as required. Experimental studies have shown that one liter of green algae culture can produce 3 milliliters of hydrogen per hour, and there is still a need to improve the efficiency of hydrogen production. Note two points: (1) Using genetic engineering techniques to improve this hydrogen-producing system could increase the hydrogen output by 10 times or more ； (2) The application of cell immobilization technology may improve the continuous hydrogen production capacity of microalgae. In countries such as Germany, Canada, and Japan, efforts are being made to establish \"hydrogen-producing algae farms\" as part of the initiatives to develop \"clean hydrogen energy\", with significant efforts being devoted to achieving large-scale production of hydrogen energy. Canada has built a plant that can produce 10 tons of liquid hydrogen per day ； Japan is focusing its research on the efficient hydrogen production by hydrogen-producing algae and photosynthetic bacteria, with the aim of developing ice-like \"grease hydrogen\" for use in rocket engines to increase the thrust of rocket launches. The United States aims to make hydrogen energy a major source of energy in the country by 2030. It seems that the use of microalgae and photosynthetic microorganisms to produce hydrogen energy holds great potential for development. IV. Making full use of organic waste or organic wastewater as raw materials to produce hydrogen energy. Researchers at Kitasato University in Japan have achieved good results in producing hydrogen from household waste, with a high yield. This hydrogen can be used directly as a clean energy source, and it also serves as high-quality material for the development of fuel cells, making it both economical and practical, with significant potential for further development. The researchers used an anaerobic bacterium, namely the AM21B strain of Clostridium, and mixed it with household waste such as chopped leftovers and fish bones, then fermented it at 37°C to produce hydrogen. The experimental results showed that 49 liters of hydrogen could be obtained from each 1 kilogram of household waste ； The household waste remaining after hydrogen production is in a paste-like state, odorless, and can be further recycled to become organic fertilizer for farmland, such as compost. It is said that Japanese researchers have developed recyclable household waste for hydrogen production, and have also created new \"fermentation equipment\" to improve the efficiency of producing hydrogen from household waste. Researchers at Harbin University of Civil Engineering and Architecture in our country have developed a technology for producing hydrogen from organic wastewater using anaerobic activated sludge as a raw material through microbial fermentation. There are several characteristics: (1) a pure strain is not used in the fermentation method ； (2) Sustainable hydrogen production without cell immobilization technology ； (3) The hydrogen production system operates stably ； (4) The purity of the obtained hydrogen is high ； (5) The yield of hydrogen production is dozens of times higher than that of similar foreign experiments. Continuous hydrogen production on a pilot scale is now available, with a yield of 5.7 cubic meters of hydrogen per cubic meter, and a purity of 99%. It is expected to enter industrial production, providing a viable biological pathway for the development of hydrogen energy. V. Developing new energy sources using CO2 waste gas as a raw material CO2, which is available in large quantities, is not only one of the major greenhouse gases but also serves as a raw material in the chemical industry. When the release and absorption of CO2 are not in dynamic balance, it inevitably has adverse effects on the ecological environment. Therefore, it is of great significance to study how CO2, as a type of waste gas, can be further transformed to achieve resource utilization. Among them, turning it into an energy source is a noteworthy research topic. At least chemical and biological methods can be used to convert CO2 into energy. (1) Chemical methods using catalysts: High-efficiency catalysts such as zeolites are employed; rhodium and manganese are adsorbed on the surfaces of approximately 99% of the active aluminum particles. At a ratio of CO2 to oxygen of 1:4, and under conditions of 300°C and 1 atmosphere of pressure, at least 90% of the CO2 can be converted into methane. If the pressure is increased to 10 atmospheres, the conversion rate can reach 100%. Of course, there is also the issue of reducing the costs of hydrogen and rhodium. The methane obtained not only provides energy and raw materials for the chemical industry, but also brings benefits by reducing the greenhouse effect, including through the reduction of CO2. q+ vx_4 (II) Biological methods using algae: As mentioned earlier, algae, particularly those microscopic unicellular organisms whether prokaryotic or eukaryotic, represent the most effective way of absorbing CO2 and using it through photosynthesis to produce green energy. During their growth, large quantities of microalgae make full use of CO2 to synthesize organic matter under light conditions, thereby storing solar energy; the biomass of these algae can be considered a huge \"energy storage reservoir.\" Therefore, it is feasible to convert them into solid fuel or dried fuel. The UK uses them for power generation ； Methane and other forms of energy can also be produced through fermentation using the biomass of various algae, including seaweeds, as raw material ； Continuous hydrogen production via the immobilization of microalgae cells is also a viable option. It is precisely because of the specific functions exhibited by various algae that they serve as both \"energy storage units\" and \"energy supply units\", from which the required clean energy can be obtained. Therefore, some experts predict that using CO2 to produce bioenergy, particularly hydrogen, will be a promising and ideal energy source in this century. VI. Microbial fermentation for ethanol production holds great potential. Ethanol, commonly known as alcohol, is used in the pharmaceutical and chemical industries. It is also a type of clean energy that is set to be developed in the future, and it constitutes one of the important renewable energies, featuring complete combustion, high efficiency, and no pollution. By using it to dilute gasoline, \"ethanol gasoline\" is produced as a substitute for leaded gasoline, with performance improved by about 15%. It is reported that Brazil has modified hundreds of thousands of vehicles to use \"ethanol gasoline\" or alcohol as fuel, **reducing air pollution**. Since ethanol shows its advantages when used as a vehicle fuel, what is the best way to produce it? Among the methods used to produce ethanol in the most economical and practical way, two aspects deserve careful consideration: one is using waste agricultural straws as raw material to produce fuel ethanol ； The second is to cultivate green algae to produce ethanol. Regarding the former, straw is a type of crop waste that is widespread around the world. In China, 650 million tons of straw are produced each year; burning it directly pollutes the environment. If even a portion of this straw were used to produce fuel ethanol, it would be beneficial for both the country and its people, as it would help protect the ecological environment. If ethanol is used as a gasoline additive to replace the current lead-containing gasoline additive—methyl tert-butyl ether (MTBE)—it would be highly beneficial for both improving the efficiency of gasoline and protecting the environment, offering significant commercial potential. Two years ago, the amount of ethanol used as fuel in the United States was 4.13 million to 5.86 million tons, accounting for approximately 83%-87% of the country’s total ethanol consumption ； At present, fuel ethanol production and the market for it do not exist in our country. However, ethanol has its advantages as an effective oxygenate additive for gasoline; in the United States, 8% of oxygenated gasoline contains ethanol as its oxygenating agent, and at present ethanol is the only alternative to MTBE. Reports indicate that at least 10,000 groundwater sources in California, USA, are contaminated by leaked MTBE, while 14% of drinking water wells across the United States are polluted. MTBE is a carcinogen for animals and also poses potential risks to human health. **On the one hand, the use of MTBE additives in gasoline is prohibited ； On the other hand, efforts are being made to actively develop the production of ethanol as a substitute. The state of California in the United States will need 35,000 barrels of ethanol per day over the next two years (note: 1 U.S. barrel = 31.5 gallons), and this demand will rise to 95,000 barrels per day after five years. To this end, ethanol producers in the United States are expanding their ethanol production capacity ； Undoubtedly, the ban on MTBE has created endless business opportunities for the ethanol industry. It can also be seen from this that seizing the business opportunities in fuel ethanol production is essential for the development of green new energy. In our country, it is entirely possible to fully utilize various types of waste straws for resource recovery or energy production, given the necessary conditions, capabilities, and technology. If 100 million tons of the 650 million tons of straw available each year are used to produce fuel ethanol, then the ethanol production volume could reach 20 million tons. According to economic assessments by relevant experts, the cost of producing ethanol from straw as a raw material is lower than that of producing ethanol through fermentation of grains ； It is higher than the cost of producing gasoline at refineries, but it remains more competitive compared to the gasoline additive MTBE. Although the use of straw to produce fuel ethanol has certain advantages and merits, its production processes and efficiency still require further investigation. As for the production of ethanol from green algae, it is quite different from the method of producing ethanol through traditional microbial fermentation. Green algae are a type of autotrophic eukaryote, among which single-celled species such as Chlorella hold great potential for developing new energy sources. A research team from a Japanese company has discovered a new strain of algae called Tit-1 in surface seawater. Similar to Chlorella, it has a diameter of about 10 μm. During the day, it converts CO2 into starch for storage, just like ordinary plants under light conditions; it can also convert starch into ethanol in low-light or anaerobic conditions. Its advantages include the fact that it does not cause environmental pollution, it can absorb CO2 from the atmosphere, **reducing the greenhouse effect**, and it produces ethanol as a byproduct. The organic combination of autotrophic and heterotrophic methods for ethanol production is a typical example with unique advantages. In summary, the six aspects mentioned above, regardless of the form in which various fuels or energy sources are obtained, are all referred to as \"green energy\" as they represent a class of clean biofuels or bioenergies that do not pollute the environment; they represent the direction in which energy development should proceed in the future. With the progress of modern civilization and the survival and development of humanity, there is an urgent need for clean new energy sources and a pollution-free ecological environment; these two aspects are closely interconnected. It is foreseeable that in the 21st century, driven by the needs of various construction projects and technological progress, green energy will surely see further development. Source: (Guangming Daily)