"Human practice is the study of how your work affects the world, and how the world affects your work."

An overview of

integrated human practice

The green synthesis of medium-chain fatty acids is the problem we are currently facing. The carbon emissions of traditional processes increase, the process consumes more energy, and the reaction conditions change to generate more by-products, which is easy to discharge a large amount of oxidation tail gas and waste acid water to cause environmental pollution. However, at present, the market demand for medium-chain fatty acids has increased, and it is widely used in textile printing and dyeing, food, medicine, daily chemicals, petrochemicals, and many other fields, with high economic value. Green synthesis process is our goal.

For our human practice, it must first serve our project, constantly improve and optimize the project in the process of practice, and adapt to the requirements of society and the environment.

We contacted the relevant government departments to find out the status of the problem we are solving. We successfully surveyed people from Italy and China who are the end users of our products and tried to interact with them to understand the current level of acceptance and concerns about the product and better improve our projects.

We have scientifically discussed with researchers with expertise in medium-chain fatty acid synthesis to improve our protocols, help us modify and refine protocols experimentally, and produce downstream industrial products.

We have communicated with specially selected experts to learn more about the development of our projects and industries, hoping to create greater industrial value. We successfully contacted experts from start-ups such as Karamay Jiangrun Chemical Materials Co., Ltd. (China) as well as universities for in-depth exchanges to help us with the development of subsequent products and the introduction into industrial production, the development of business models, market research and possible opportunities to launch our products in the market.

We take into account all technical, safety, ethical and socio-cultural issues related to implementation and complement our values with relevant experts.

Design the

framework of our human practice

In 2021, the total output of UCO (used cooking oil) in the world is about 6.4 million tons, of which China produces about 1.86 million tons, accounting for up to 29%, so our project is very important to the world. How to make our project a good project responsible for the world is a problem that we human practice has to think about, so we have carefully formulated the framework of human practice.



Figure 1 Mind Map of HP

Our journey of

integrated human practice

Stage 1: discovering and understanding the problem in depth

● Brainstorm and spot problems

During the brainstorming process of the OUC-China team, one of the team members thought of a friend of hers who told her that the current fine production of medium-chain fatty acids is difficult and polluting, such as producing a large amount of acid water, because her hometown is Karamay, the oil city of China, and her family works in a local factory that produces medium- and long-chain fatty acids. Through data search, we found that medium-chain fatty acids have high industrial value, so we began to think deeply about how to use synthetic biology to better solve this problem.



Figure 2 Karamay Black Oil Mountain

● Explore context

Through the survey, it has found that the current biomass extraction pathway has limited sources and low concentrations, such as MCFAs extracted from coconut and palm kernel accounting for 7.9%-15% of the total fatty acids, and the yield is low. Synthesis from fossil resources is not sustainable.

What raw materials can be used to meet our green and sustainable requirements?

The team members thought hard, in the process of eating barbecue together, looking at the barbecue with nourishing oil, they carefully found that edible oils are actually rich in fatty acids, but these oils are difficult to reuse after processing food, resulting in a waste. Our team came up with a new idea: why can't we reuse these waste oils and fats to produce medium-chain fatty acids from them?



Figure 3 Karamay Black Oil Mountain

So, we found the real problem we want to solve: to solve the green synthesis of medium-chain fatty acids from kitchen waste oil.

Then we would like to explore the communities, institutions, or individuals affected by the problems. We started thinking about who would benefit from it and who would oppose the project.

● Engaging With Those Affected

Adhering to people-oriented social values, we have identified five categories of stakeholders: restaurant operators, governments, kitchen waste oil recycling companies, medium-chain fatty acid synthesis enterprises, and the public.

We first interviewed the manager of the Yushan Canteen at Ocean University of China, who is the most direct contact with the raw materials of kitchen waste oil and a potential stakeholder. Next, we walked into the government department to understand the current situation and policies of kitchen waste oil recycling. At the same time, the company was investigated to understand the current situation of waste oil recycling and the current status and problems faced by medium-chain fatty acid synthesis enterprises. We insist on doing projects that are responsible for the world, first and foremost projects are responsible for everyone. Adhere to a human-centered mindset and consider whether there are concerns and objections to our project from a wider range of stakeholders.

Stakeholders: Restaurant operators

Canteen Manager of Yushan Campus, Ocean University of China

● Why are we talking to him?

The university has a large population and a large daily catering supply, so the amount of kitchen waste oil generated is also innumerable, and we can understand the most real situation of kitchen waste oil treatment through interviews. The staff's treatment of kitchen waste oil can help us better understand the treatment of kitchen waste oil and the existing problems.

● The highlights

"At present, the kitchen waste oil produced by colleges and universities and some units with a large population is through centralized recycling of kitchen waste oil, and then handed over to the corresponding departments for unified and centralized treatment, most of which are made into fuel oil, soap, combustion power generation, etc. after treatment, and the treatment methods are diverse." However, at present, the economic value and environmental benefits brought by the technology of kitchen waste oil treatment in China need to be improved, so more and better treatment methods are expected. ”

● Summary

Through the communication with the canteen manager, we understand that the current way of treating kitchen waste oil, economic value, environmental benefits, etc. need to be improved, which makes us more aware that there is still a lot of value space waiting for us to develop, using biosynthesis technology, using kitchen waste oil as a substrate for the synthesis of medium-chain fatty acids and their derivatives to improve the added value of products, which is expected to improve economic and environmental benefits.



Figure 4 Interview with the restaurant manager

Stakeholders: relevant government departments

Director of the Natural Resources Administration

● Why are we talking to him?

Zenggui Liu, director of the Natural Resources Management Bureau of Yantai City, Shandong Province, China, has a holistic understanding of the current treatment of kitchen waste oil.

● The highlights

"The treatment of kitchen waste oil is different in different regions. As far as the current situation is concerned, the local government will not uniformly recycle kitchen waste oil, but it will be recycled and used by enterprises. However, the subsequent treatment is mainly used as garbage to generate electricity. ”

● Summary

According to the survey, the current utilization rate of kitchen waste oil resources is low, and there is no suitable treatment method to reuse waste, which will produce a large waste of resources. This is true not only in much of China, but also globally, so coming up with a better solution is imperative. This also provides an opportunity for our new treatment method to efficiently process and utilize kitchen waste oil to produce medium-chain fatty acids.



Figure 5 Interviews with environmental companies

Stakeholders: Food waste oil recycling enterprises

Beijing Enterprises Group Shifang (Shandong) Environmental Protection Energy Group Co., Ltd

● Why are we talking to him?

The company carried out the first project in China to produce refined natural gas from biogas generated by food waste, and responded to the construction of a waste-free city with the resource utilization of food waste.

● The highlights

"The utilization rate of food waste resources has reached more than 95%, and the treatment scale has increased to 300 tons per day. The industrial-grade oil mixture extracted from food waste can be used as a raw material for biodiesel. ”

● Summary

Unlike what we learned in previous interviews with the government, some enterprises with more advanced counts also have new technologies and ways to use kitchen waste oil, such as the production of biodiesel. We visited the transfer process of the transfer station, and at the same time learned about the advanced treatment process of kitchen waste oil, and the subsequent utilization rate as a biodiesel raw material is relatively high. But the current available method is relatively single, only biodiesel can be synthesized as an industrial raw material, and the industrial value has room for improvement, so it also inspires us to think about the industrial value of our project.



Figure 6 Interviews with Waste oil reuse companies

Stakeholders: Medium-chain fatty acid synthesis companies

Ming Ni Karamay Jiangrun Chemical Materials Co., Ltd

● Why are we talking to him?

Ming Ni, technical leader of Karamay Jiangrun Chemical Materials Co., Ltd., understands the current market demand and technical difficulties of medium-chain fatty acid synthesis.

● The highlights

"At present, the synthesis field of medium-chain fatty acids is relatively niche, and the production of medium-chain fatty acids extracted from traditional fossil raw materials is small, the cost is higher, and most companies choose to produce long-chain fatty acids with larger output, and enterprises also hope to cooperate with better technologies." In the case of low production of medium-chain fatty acids, the production of higher value-added industrial products can be considered to reduce production costs."

● Summary

With his feedback, the team members further explored the industrial value of the project. We can complement our project by perfecting our solutions to produce high value-added industrial products.

Stakeholder: Broader consumers

Under the changing climate change conditions, environmental pollution has become a public concern, and the public's attitude towards pollution is also changing. The dynamic relationship between public attitudes and synthetic biology is complex, so we investigated public attitudes.

For our project, we designed a questionnaire —— a public survey of food waste oil, to ask the public for opinions and suggestions, aiming to understand the public's understanding of the current status of food waste oil disposal and the recognition of reused products.



Figure 7 Mass Interview

We design a reasonable questionnaire model, which is both scientific and innovative. The team members conducted in-depth surveys with the public, as well as people in different regions, including people in China, India, Italy and other countries.

The results of the questionnaire were collected and analyzed as follows, which made it clearer that the public's concerns about synthetic biology protocols and attitudes towards new synthesis protocols of medium-chain fatty acids.



Figure 8 Survey Results（1）

According to the survey of "whether kitchen waste oil is necessary for recycling and reuse", a small number of positive and negative attitudes, most of them have a neutral attitude, which also shows that the current public lack understanding and awareness of the current situation of food waste oil reuse. These inspires our project to popularize the current status of kitchen waste oil to the public (current production volume, resource reuse, the utilization rate of resources) and the knowledge to improve the public's awareness of the current situation of kitchen waste oil.

As an important organic chemical raw material, MCFAs have a wide range of applications in food, medicine, agriculture, chemical industry and other fields, and the market demand is large. The public's attitude towards this program is relatively positive, reflecting the public's high tolerance and acceptance of this type of product, and also providing recognition and support for us to continue to carry out the project plan.

How to make the public recognize our products, the survey results show that the most concerned factors for users to use products with peace of mind are understanding the production process and principle of products, the certification of relevant departments such as the government, and the test report of product ingredients. This project can increase users' peace of mind by strengthening the publicity and providing relevant proofs in these aspects.



Figure 9 Survey Results（2）

At the same time, in response to the current concerns of the public of medium-chain fatty acids, the most concerned is that the harmful substances of kitchen waste oil cannot be removed, and a total of 198 people chose this option, accounting for 78.26% of the total effective times. This shows that the safety of kitchen waste oil treatment is the most concerned issue of respondents, so it is also the direction of our project. A lack of trust in the actual processing is the second concern, with 136 people choosing this option, accounting for 53.75% of the total number of validities. This shows that the respondents have a certain sense of distrust in the actual operation of kitchen waste oil treatment, and also reflects that there is a certain deviation in the public's understanding of this field, and through our team's comprehensive human practice, we hope to improve the public's trust in this type of technology. Another 151 people chose this option they did not know much about some of the principles of treatment separation, accounting for 59.68% of the total effective times. This shows that the respondents have insufficient understanding of the principles of kitchen waste oil treatment and lack of relevant knowledge, which leads to worry.



Figure 10 Survey Results（3）



Figure 11 Survey Results（4）

In summary, the respondents' concerns about the treatment of food waste oil are mainly reflected in biosecurity, and the removal effect of harmful substances, the degree of trust in the actual treatment process, and the degree of understanding of the treatment principles are different from our expectations. To address these concerns, it is necessary to strengthen the safety of our projects, promote and educate the technology of food waste oil treatment, and increase public awareness and trust in food waste oil treatment.

Stage 2: What can be a good solution

● Be clear about our values

From our stakeholder consultations, we come back with a lot of values and problems that need to be solved, thinking about how we can solve them. When designing solutions, we take into account the valuable input of each stakeholder that we believe will be a good solution to the green synthesis of medium-chain fatty acids using kitchen waste oil as raw materials. But we can't fully involve any one stakeholder due to time and space constraints. We identified the values to prioritize and the issues to be addressed in our projects based on representative stakeholders

Our first and fundamental task is to solve the problem of green production of medium-chain fatty acids. Therefore, designing an innovative experimental protocol is the focus of our project, using the newly discovered M. in the mangrove forests of Hainan aphidis XM01 (Black Powder on Mohs), which regulates its metabolic pathway to synthesize medium-chain fatty acids, see our Experiments section for details.

Our interactions with stakeholders also help us better develop a project that is responsible for people and the world. Through continuous communication with stakeholders, understanding the concerns of a wider range of consumers about biosecurity and food safety has guiding significance for us to develop solutions, and pay more attention to the safety of adding medium-chain fatty acids to food. In continuous communication with stakeholders, getting feedback from each stakeholder is important to our project. In addition, we recognize that some of the public's concerns about safety may stem from a lack of understanding of synthetic biology. To address this, our Science Communication team conducts science popularization activities in education, as detailed in the Education section.

Our communication with stakeholders gives us a clearer understanding of the industrial value of the project, and also allows us to further think about how to improve the industrial value of the project, so that we can not only produce medium-chain fatty acids, but also downstream industrial products with higher added value by extending the product chain.

Finally, as a product for industrial application, we need to consider our economic cost and low cost, and form a scheme that is accepted by more traditional craft enterprises in terms of economy and cost.

• Green synthesis of medium-chain fatty acids

• Be focus on food safety and biosecurity

• Be higher industrial added value

• Be high economic value and low cost



Figure 12 Our value

Stage 3: Conceive and design our solutions

Our team connects experts and academics in various environmental fields and medium-chain fatty acid synthesis with their experience in research, implementation, and modelling. These conversations help drive the ideation and design of technically sound, safe and effective synthetic biology solutions. In this phase, our project has evolved a lot because it has changed and adapted to the suggestions and insights received.

● Biosafety improvements

According to stakeholder feedback, in the process of designing the experiment, the newly discovered M. in the mangrove forest of Hainan was used to understand the newly discovered M. aphidis XM01, the regulation of its metabolic pathway to synthesize medium-chain fatty acids, the first thing to consider is food and biosafety. Because part of the use of medium-chain fatty acids is that they can be added to food as food additives, subject to the use of raw materials - kitchen waste oil, the first task is to clarify whether kitchen waste oil is safe in the production of food ingredients. Therefore, we consulted with experts on the environment to provide valuable advice on biosecurity.

Yangguo Zhao is a professor at the School of Environmental Science and Engineering, Ocean University of China



● Why are we talking to him?

Professor Yangguo Zhao has been deeply engaged in the field of hazardous substance treatment for many years, has an in-depth understanding of various harmful substances, and the hazards to the environment and food, and has presided over and participated in many projects such as major national science and technology projects, the National Natural Science Foundation of China, and provincial and ministerial funds.

● The highlights

"The polycyclic aromatic hydrocarbon benzopyrene (BaP) is a very difficult compound to biodegrade and has trigenic properties. At present, there have been many studies, using active pollution or pure strains to carry out research on degradation performance, and achieved certain results, so there is no problem whether what you said is feasible.

However, there are still many bottlenecks for practical applications, such as complex pollutant structure, the need for a variety of biological synergistic degradation; slow biodegradation rate; incomplete degradation products, high toxicity of intermediate products, and harsh environmental conditions, so there are no cases of large-scale application. ”

● Summary

The raw material we chose is kitchen waste oil, but in the process of processing kitchen waste oil, Professor Zhao Yangguo pointed out that benzopyrene is a potential factor affecting food safety of kitchen waste oil, so we should consider how to degrade benzopyrene in the project, which is also reflected in our design part, according to the previous stakeholders and professors' attention to food safety, we tried to treat harmful substances.

Jiangbing Qiu is a professor at the School of Environmental Science and Engineering, Ocean University of China



● Why are we talking to him?

Professor Jiangbing Qiu mainly studies the bioavailability of shellfish toxins, and has done more research on toxic substances, which can help us deal with harmful substances.

● The highlights

"PAHs are widely distributed in the environment, present in the atmosphere, soil, water, food and petroleum fuels, and can enter human animals or humans through different pathways, and are carcinogenic and mutagenic. There are currently three main detection methods. The method of liquid-liquid extraction or solid phase extraction was used to extract PAHs in water samples; GC-FID detector was used to establish an analysis method for PAHs, determine the composition and concentration of PAHs in the mixed standard solution, and draw a standard curve. The GC-FID detector was used to determine and analyze the composition and concentration of PAHs in the water sample. "

● Summary

Learn how to separate PAHs and detect PAHs. Asking about the severity of the hazards of PAHs further verified that it is necessary for our project to pay attention to harmful substances, so we also laid the foundation for how to better detect and degrade PAHs industrially.

● Kill switch

Qian Wang is a professor at the National Sugar Engineering Technology Research Center of Shandong University



● Why are we talking to her?

Qian Wang, State Key Laboratory of Microbiology, Shandong University, mainly researches the use of synthetic biology methods to redesign, construct and regulate the metabolic network of cell factories to achieve efficient carbon conversion efficiency artificial pathway.

● The highlights

"N-acetylneuraminic acid cannot be produced in E. coli and is not easily absorbed and degraded, so it is a more suitable choice as an inducing substance. For switches designed to rely on inducers that are already present in some organisms, such as glycine ribose switches, you can try to perform site mutations to raise the threshold to avoid the influence of glycine and other substances contained in chassis organisms, thereby reducing the interference of endogenous substances"

● Summary

Through discussion with Professor Qian Wang, we identified N-acetylneuraminic acid as an inducer of our suicide switch, which can greatly avoid the interference of endogenous substances, which will greatly improve the sensitivity of the suicide switch and provide a new idea of suicide switch.

● Extend the industrial chain

After communicating with Professor Guanglei Liu , it was found that the corresponding enzymes could catalyze the production of medium-chain olefins and 10-hydroxycapric acid by the corresponding enzymes α the production of medium-chain olefins. According to Professor Liu Guanglei, since the beginning of the industrial era, human consumption of natural resources has increased sharply, and the reserves of petrochemical raw materials have decreased sharply, and it is important to develop sustainable fossil fuel alternatives. Biofuels produced from biological resources are renewable and more environmentally friendly. Among the various biofuels, bioethanol and biodiesel dominate the current global market. However, it is generally accepted that ideal biofuels are biohydrocarbons, especially medium and long-chain aliphatic alkanes or olefins, as they highly mimic the chemical composition and physical properties of petroleum-based fuels. It is worth noting that in addition to being a biofuel molecule, α-olefins are widely used in the manufacture of lubricants, polymers and cleaning agents. Therefore, α olefins and 10-hydroxycapric acid are produced as downstream high value-added products produced by us with medium-chain fatty acids.

● Actual production

Professor Xiangming Qi, School of Food Science and Engineering, Ocean University of China



● Why are we talking to him?

Xiangming Qi, School of Food Science and Engineering, Faculty of Life Sciences, Ocean University of China. At present, he is mainly engaged in biotechnology research and development using food resource reuse.

● The highlights

"The oil-water reaction system involves heterogeneous reactions, and the design of the fermenter is difficult. If the density difference between the lipid droplets and the fermentation broth in the separation device is large, the suspension can be used for separation, which is more efficient, and it is recommended to determine the specific size through software simulation."

● Summary

In the process of communicating with Professor Qi, the problems existing in the process and the problems in the machinery were clarified, and the equipment required was designed through flow simulation.

Professor Guanglei Liu is a professor at Ocean University of China



● Why are we talking to him?

Guanglei Liu is a professor at the College of Marine Life Sciences, Ocean University of China, and his main research interests include key protein functions, pathway analysis and reconstruction, and regulatory mechanisms in yeast carbon metabolism and product synthesis.

● The highlights

"In view of the problems of multi-phase mixing and low sedimentation efficiency in the current fermentation plant, multi-phase flow paddles and accelerated sedimentation devices can be adopted to optimize the device."

● Summary

Both Professor Li and Professor Qi said that the heterogeneous system of heterogeneity has certain challenges and difficulties in device design, which also inspired us to make subsequent improvements. In the process of communication, the actual production is guided through the optimization of the design scheme, and the design scheme is improved through problem feedback in the actual production process.

Professor Li Jing is a professor at Ocean University of China



● Why are we talking to her?

Li Jing, a professor at the School of Marine Life Sciences, Ocean University of China, focuses on the research and development of new marine anti-tumor drugs, elucidating the mechanism of action of new drugs, and discovering new drugs and targets.

● The highlights

"For the current fermentation plant, the blade structure is relatively perfect, and other aspects can be considered to optimize the plant."

● Summary

Professor Li said that the heterogeneous system of multiple phases has certain challenges and difficulties in device design, which also inspired us to make subsequent improvements. In the process of communication, the actual production is guided through the optimization of the design scheme, and the design scheme is improved through problem feedback in the actual production process.

Professor Wang, Institute of Microbiology, Chinese Academy of Sciences

● Why are we talking to her?

Professor Wang has been deeply engaged in the field of microbial fermentation for many years and has profound knowledge in microbial fermentation.

● The highlights

"In the fermentation process, liquid stratification is prone to occur, and the separation of components of different components in the later stage needs to pay attention to relevant treatment and suitable product testing."

● Summary

Through communicating with the research director of the Institute of Microbiology, I learned that there are certain difficulties and challenges in the separation of products after fermentation, and at the same time, it is necessary to control the state of the product during the fermentation process in order to optimize the fermentation effect. At the same time, he followed the project team to learn the use of transmission electron microscopy, meteorological chromatography and other instruments for sample processing and sectioning, downstream detection.



Figure 13 Communication with Professor Wang

Stage 4: Carry out our solutions

● Kill switch implementation

Based on the recommendations of stakeholders and environmental experts, we discussed and implemented options for the degradation of benzopyrene. From the preliminary determination of a benzopyrene receptor, it is composed of AHR (Benzopyrene receptor) and ARNT (AHR nuclear translocator protein) two proteins, AHR and benzopyrene after binding, combined with ARNT to form a dimer, start downstream promoter expression protein. But we talked to PI about our ideas and he told us that by measuring benzopyrene in kitchen waste oil, we found that the content was small, and the biosensor often failed to reach such a low threshold, so he suggested that we replace the switch. Through modeling, we found that the sensor really had difficulty detecting lower benzopyrene and decided to replace the switch. We hope to use the ribose switch as a suicide switch for engineering bacteria, but there are some doubts about the choice of ribose switch and the specific implementation details, so we communicated with Professor Wang Qian of Shandong University about the design of the suicide switch, and the professor gave us many valuable suggestions, we finally chose the NeuAc ribose switch, and after subsequent consideration, we established the red light as the switch to start benzopyrene degradation.

However, due to the time constraints of the current project, the experimental inspection of the red light switch was not carried out in time, and it was also found that we have a certain boundary on food additives, which is not static, and we can expand our boundary through the subsequent experimental verification of suicide switch and the detection and degradation of other harmful ingredients.



Figure 14 Switch Improvement

● Hardware implementation

Based on the advice of relevant experts, we found a manufacturer to customize a standardized miniature tank (lacking blades, separators, multiple pipelines, etc.), and the missing parts will be filled with our 3D printed models to test the effect of different shapes, and handed over to stakeholders to get more feedback and facilitate improvement.

We design, test and optimize the hardware of our project based on customized, modular micro-fermenters in the laboratory. Starting from the selection of fluid simulation software for multiphase fluid simulation, we continue to communicate with professors, iterate three generations of propeller design, and constantly improve to adapt to actual production needs. At the same time, the innovative design accelerated the settlement box and 3D printing, and finally verified that the two parts of the designed hardware are easy to produce and assemble and have superior performance, see the hardware section for details.



Figure15 Hardware implementation

● Project outlook

Shanghai Jingkey Biotechnology Co., Ltd

● Why are we talking to her?

Jingkey Biotechnology is an innovative enterprise focusing on biotechnology research and development. With the research and development, production and sales of ELISA kits and biochemical kits, and continuously upgrading antibody research, and has relevant experience in the detection of medium-chain fatty acids. In actual experiments, we found that each detection of medium-chain fatty acids requires complex extraction steps for gas phase liquid chromatography, which requires a lot of manpower and material resources. So we are looking for more convenient means of detection.

● The highlights

"There are no boxes on the market that detect medium-chain fatty acids, and the detection is very poor. The medium chain can only be tested on the machine LC-MS measurement."

● Summary

It is difficult to know the convenience of detection of medium-chain fatty acids through communication, and it also inspires us to continue to improve the detection of medium-chain fatty acids in the future.





To be a responsible project:Connect with society

Throughout the process of human practice, we refine this project from practice, while our research follows the modern gold standard of responsible innovation, and we maximize the use of advice and resources from industry and stakeholder participation to improve the project. As part of the 3Rs, "reflection" helps us consider our goals and inspirations, which in turn helps us identify scholars and groups to consult. On "responsibility", we explore the limits of project capabilities, dig deeper into opportunities in the market, consider how to innovate sustainably, and discuss with stakeholders to better align with their requirements, providing an inclusive and progressive tone. We closed the feedback loop in "response" and leveraged the human practices framework to enable human practices throughout the project. We are very grateful to everyone involved in every stage of our process of shaping the design, perfection, and final optimization of our projects into our products.

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[2] Yangyang Li, Yiying Jin, Jinhui Li, Yixing Chen, et al. Current Situation and Development of Kitchen Waste Treatment in China[J]. Procedia Environmental Sciences, 2016, 31:40-49.

[3] Talha Ahmad, Tarun Belwal, Li Li, Sudipta Ramola, et al. Utilization of wastewater from edible oil industry, turning waste into valuable products: A review[J]. Trends in Food Science & Technology, 2020, 99:21-33.