Chapter 354 - 172: Owen’s Bacteria

Chapter 354: Chapter 172: Owen’s Bacteria

The advantage of this technology is that it’s environmentally friendly.

The disadvantage is its extremely low efficiency. Each cubic meter of high-carbon nutrient medium can only generate 10 to 20 kilowatt-hours of electricity. In contrast, direct combustion can produce around 500 kilowatt-hours of electrical energy.

The two aren’t even comparable.

Moreover, the so-called power generation per cubic meter of high-carbon nutrient medium is a result achieved under ideal laboratory conditions.

For example, in a paper published on June 23, 2024, a research team led by Chinese-American scientists Duan Xiangfeng and Huang Yu developed a new type of microbial flow fuel cell (MFFC). By using artificial electron mediators to efficiently transfer bacterial metabolic electrons in a flowing medium, they achieved a maximum power density of 17.6 mW/cm² (equivalent to 176 watts per cubic meter).

According to the data Jiang Miao had researched, their experimental system could only operate for about 90 hours in a lab environment before its efficiency plummeted.

Based on this data, after converting to a cubic meter basis, the system could generate approximately 15.84 kilowatt-hours during its stable peak power phase. Including the subsequent low-power generation, the total would be about 20 kilowatt-hours at most.

In contrast, microbial fuel cells under non-laboratory conditions only have a maximum power output of a few dozen watts per cubic meter.

Of course, under non-laboratory conditions, the power generation period extends to several months because the bacteria decompose organic matter more slowly. As a result, the total power output is still around 10 to 20 kilowatt-hours.

If a power generation rate of 176 watts per cubic meter could be maintained for one month, the monthly output would be 126.72 kilowatt-hours. Over two months, it would be 252 kilowatt-hours, and over three months, it would reach 378 kilowatt-hours.

So, is it possible to achieve stable, long-term power generation under high-power conditions?

The answer is yes.

Currently, the energy conversion efficiency of exoelectrogenic bacteria is 10-30% under non-laboratory conditions, while it can reach 60-70% in a lab environment.

Furthermore, one particular point requires special attention.

The organic matter in the nutrient medium is not equal to the organic matter consumed by the exoelectrogenic bacteria.

Exoelectrogenic bacteria can only break down and digest a small fraction of the organic matter.

For example, among exoelectrogenic bacteria, *Pseudomonas aeruginosa*’s diet only includes carbohydrates

such as glucose, xylose, and starch; nitrogen-containing compounds like amino acids and urea; fatty substances like triglycerides and phospholipids; and aromatic compounds.

From this, it’s clear that many exoelectrogenic bacteria cannot directly digest the cellulose, hemicellulose, and lignin found in cattle and sheep manure.

If the cellulose, hemicellulose, and lignin could be broken down into glucose, monosaccharides, and aromatic compounds, then they could be directly utilized by some exoelectrogenic bacteria.

In fact, a small number of exoelectrogenic bacteria can also break down cellulose, hemicellulose, and lignin, but their decomposition efficiency is relatively low.

What Jiang Miao needed to do now was develop an exoelectrogenic bacterium that could efficiently decompose cellulose, hemicellulose, and lignin.

In fact, a research team in the European Union had already used genetic engineering to modify *E. coli*, giving it the ability to generate power through metabolism while also enabling it to break down some hemicellulose.

This kind of directed research was not difficult for Jiang Miao.

Screening and cultivating highly efficient, specialized exoelectrogenic bacteria was Jiang Miao’s specialty.

He didn’t even need to use genetic engineering. He could simply force the exoelectrogenic bacteria to mutate by applying various artificial environmental pressures. Bacteria reproduce and mutate extremely quickly, which is highly advantageous for cultivating specialized strains.

Using methods such as electric currents, varying pH levels, chemical agents, freezing, high temperatures, and ultraviolet radiation, combined with various simulated cultivation environments, it took Jiang Miao only three days to obtain a specialized strain of exoelectrogenic bacteria.

The parent strain for this exoelectrogenic bacterium was *Erwinia billingiae* strain QL-Z3, from the genus *Erwinia*. In its original form, when lignin was its sole carbon source, its lignin degradation rate could reach 25.24%.

After multiple rounds of mutation, screening, and cultivation, the resulting bacterium could not only degrade lignin but also cellulose and hemicellulose, with a maximum degradation rate of around 97%.

Of course, achieving this optimal degradation rate was not so easy.

To be precise, for this brand-new bacterium, which Jiang Miao named the "Owen Power Generation Bacteria," achieving the optimal degradation rate required meeting four very strict conditions:

First, the ambient temperature must be between 20 and 28 degrees Celsius.

Second, it requires symbiosis with a specific gram-negative bacterium. During its growth, this gram-negative bacterium secretes a substance known as a quorum-sensing signal molecule. When the bacterial density reaches a certain threshold, these signal molecules activate a series of gene expressions, promoting the reproduction of both itself and the Owen Power Generation Bacteria. The metabolic products of the two are mutually beneficial.

Third, a specific dose of soy genistein (a pseudo-estrogen) must be added to further stimulate the Owen Power Generation Bacteria to reproduce and degrade lignin, cellulose, and hemicellulose.

Fourth, the oxygen concentration in the environment must reach 32%.

In fact, during his experiments, Jiang Miao did discover other mutant bacteria with fewer requirements for degradation, but it was precisely because the conditions were so few that he dared not use them.

Fewer restrictions on reproduction meant a greater ability to spread widely in nature.

After all, Owen’s Bacteria are plant-saprophytic bacteria. If one with such a powerful ability to degrade lignin, cellulose, and hemicellulose had no reproductive restrictions, it could wipe out all the world’s plant life in just a few years.