Study: Bacteria produce an important industrial product from wastewater Science

There are many challenges when considering scaling up chemical production in wastewater.

Butanediol (multifunctional) alcohol is used in polyester production and in a variety of industrial applications from pharmaceuticals to cosmetics.

While its production has traditionally relied on energy-intensive processes, a Chinese research team has taken a step forward in producing it using bacteria and industrial wastewater.

In a study published in the latest issue of the journal Nature Sustainability, the research team — which includes researchers from the Chinese Academy of Sciences’ Shenzhen Institute of Advanced Technology and Harbin Institute of Technology — revealed details of their new method, and how they succeeded in using fast-growing marine bacteria…” Vibrio natrigens” was used for this purpose after they genetically engineered it to tolerate industrial wastewater pollutants.

Role of genetically engineered bacteria

Research teams have previously tried to use bacteria to treat industrial wastewater, but these biological solutions did not withstand the pollutants the bacteria removed.However, a Chinese team claims to have succeeded in overcoming this problem through genetic engineering.

Vibrio natrigens bacteria generally have exceptional tolerance to high salt concentrations and the ability to benefit from a variety of carbon sources and, with genetic modifications introduced by researchers, also have the ability to tolerate pollutants and heavy metals in wastewater. Purify the water, but also convert those pollutants into useful products like butanediol alcohol.

A press release published on the official website of the Chinese Academy of Sciences states, “Real industrial wastewater, with its composition of major organic pollutants, heavy metals, and complex pollutants, is toxic to bacterial cells and difficult to treat efficiently. It contains high amounts of salt and dissolved oxygen, therefore, using wastewater as a raw material for pectin difficultRhea“.

To overcome this problem, the researchers used genetic engineering to help the bacteria cope with the pollutants, and they trained them to use different metals and different sources of carbon to produce a semiconductor material from wastewater used in the production of butanediol alcohol. .

Manufacturing process steps

The genetically engineered bacterial strain produced hydrogen sulfide from the pollutant, which was instrumental in facilitating the production of cadmium sulfide nanoparticles, an efficient light-absorbing semiconductor.

These nanoparticles, known for their biocompatibility, are activated by sunlight, enabling their efficient use in greatly enhanced production of butanediol alcohol.

The amount of material produced using this new approach was shown to exceed that achievable with bacterial cells alone. Also, the results showed the scale of the process as the research team succeeded in purifying 5 liters of wastewater with the support of sunlight.

Therefore, the method devised by the researchers not only has a low carbon footprint, but also reduces production costs, resulting in an overall lower environmental impact compared to both traditional bacterial fermentation and butanediol alcohol production methods based on fossil fuels.

Alternative method

Ibrahim El-Sherbini, founding director of the Nanoscience Program at Zewail City of Science and Technology in Egypt and director of the city’s Materials Science Research Center, has some reservations about the innovative method, which he describes as “different.” including the unsuitability of this method for industrial use.

Al-Sherbini says – in telephone reports to Al Jazeera Net – “Industrial wastewater varies from one industry to another and from one region to another, so to use this method, industrial wastewater must be selected with special specifications. It contains minerals that bacteria can metabolize to start the production process.” This makes widespread use of this site difficult.”

The second reservation pointed out by El-Sherbini is that the treated wastewater will contain nanoparticles of cadmium sulfide, which is known for its biocompatibility, which means it does not harm human health, but this cannot be said absolutely.

He says, “It is known that this substance leaches into the human body in large quantities and becomes a substance with a toxic effect, so there must be a mechanism to remove water containing this substance after receiving the necessary chemicals. Must be prepared.”

El-Sherbini does not believe that using it to irrigate ornamental trees would be an appropriate solution, because water containing cadmium sulfide could seep into groundwater and reach humans in some form. What is required from wastewater?

The challenge of practical application

The research team is aware of these challenges pointed out by El-Sherbini, as their current challenge is to find an economically viable and environmentally friendly approach to industrially expand the scope of this technology.

Xiang Gao, a researcher at the Shenzhen Institute of Synthetic Biology of the Chinese Academy of Sciences and lead researcher of the study, told Al Jazeera Net in a special report via email, “In fact, we did our experiments with both 30 liters. and 100-liter bioreactors, and we treated 5 liters during the experiment. We produced 50 g of (2,3-butanediol).

He adds, “There are still many challenges when considering scaling up chemical production in wastewater. These challenges include the presence of unwanted impurities in the reaction process, sunlight that changes from day to day and from one area to another, and the complex steps involved in chemical separation and post-treatment.” Production of necessary goods.

He continues, “These issues must be resolved for large-scale applications to succeed in the future. We also need to increase the economic value of the treatment by producing multiple products, which we succeeded in doing after publishing the study.”

He continues, “We produced chemicals other than 2,3-butanediol. For example, we produced isoprene, an essential component of synthetic rubber.”