Around 40% of shrimp is discarded as waste, mainly consisting of heads and shells. Some of these residues are used as feed supplements in animal and aquaculture industries; however, a significant percentage remains unused.
Shrimp waste is rich in nutrients, including proteins, lipids, and pigments, which have significant commercial value.
In this regard, a team of researchers from Lovely Professional University, the National Research and Innovation Agency, HealthPlix Technologies Private Limited, the University of North Carolina, Ibn Zohr University, Tiradentes University, Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir, and São Paulo State University (UNESP) published a scientific review evaluating the scientific literature on eco-friendly and safe alternatives for valorizing shrimp farming waste.
The report explores various methods of valorizing shrimp waste that are environmentally sustainable and safe for human and animal health. The document covers multiple topics, including the extraction of valuable compounds, converting shrimp waste into energy, and using the waste as a sustainable source of animal feed and fertilizers.
Waste generation in shrimp farming
The significant increase in shrimp production is a serious concern due to the generation of large amounts of waste. The generation of abundant waste poses a threat to the environment due to its chemical nature and easy degradation.
The byproduct generated from shrimp ponds contains a considerable amount of organic matter resulting from unconsumed feed and shrimp metabolic waste. This byproduct has the potential to contaminate not only the aquaculture environment but also adjacent waters.
On the other hand, shrimp farmers generally use chemicals (formalin, sodium chloride, potassium permanganate, trifluralin), medications (florfenicol, enrofloxacin, sarafloxacin, oxytetracycline), and supplements (prebiotics, phytochemicals, and organic acids) to keep the shrimp healthy. However, most of these products end up in waterways.
Strategies for shrimp waste utilization
Shrimp shells contain beneficial chemical substances: calcium carbonate (20-50%), protein (20-40%), and chitin (15-40%). The potential use of residual shrimp shells has largely been overlooked.
In recent decades, scientists have been trying to find sustainable ways to maximize the use of shrimp waste. Dried shrimp shells have a value of approximately $100 per ton.
Shrimp shells can be processed and crushed to extract various metabolites for use in animal feed, microbial growth media, and bioadsorbents.
Shrimp waste and valorization
Valorization of waste includes recycling, reusing, and composting different waste materials and converting them into valuable materials, fuels, chemicals, or other sources of energy.
Furthermore, valorizing shrimp waste offers economic and environmental advantages by bioprospecting the waste and reducing issues that arise with conventional disposal methods.
Ecological methods for a green economy can effectively valorize shrimp waste. Different methods are applied for the processes of deproteinization and demineralization to replace hazardous chemicals like HCl and NaOH.
Approximately 30% of chitin and other materials such as pigments, proteins, and minerals can be extracted from shrimp waste.
Japan has dominated chitin/chitosan production for at least 30 to 40 years. The global market for chitosan was estimated at around $476.6 million in the year 2016.
Valorization through fermentation
According to the study, two methods are adopted to utilize shrimp waste:
- Subjecting the shrimp waste to a sequential alkaline solution to remove minerals, lipids, and proteins. However, apart from chitin, no other material can be extracted.
- Recovering proteins through autolysis or hydrolyzing with exogenous proteinase. The resulting protein hydrolysate leads to the production of a bitter taste and fishy odor.
Fermentation offers an advantage to overcome these limitations by fermenting shrimp waste with lactic acid bacteria. This method ensures the recovery of chitin, proteins, and carotenoids without polluting the environment.
Challenges in the processing and utilization of waste
Existing methods for valorizing shrimp waste are expensive, destructive, and uneconomical. Shrimp waste undergoes several rounds of chemical processes to obtain high-quality products.
To achieve greater operational efficiency, a substantial investment in the application of advanced technology is needed to reduce waste, maintain product quality, improve performance, and increase product shelf life.
On the other hand, the bioconversion of shrimp waste has limitations that hinder its advanced applicability. The processing rate is significantly slower than chemically mediated processes. The unpleasant odor generated by the bioprocessing of shrimp waste is also a problem.
Furthermore, while microorganisms are applied for the processing of shrimp waste, there is a higher possibility of unwanted microbial growth, leading to contamination, which negatively affects shrimp waste processing.
Conclusion
“The article highlights the growing concerns about the expansion of unused shrimp waste in major producing countries. The voluminous loss of nutrient-rich shrimp waste is a serious cause for concern,” conclude the researchers.
They also indicate that the chemical methods used for shrimp waste valorization have significant ecological disadvantages associated with them.
Finally, products from shrimp waste processing have advanced applications in the agricultural, pharmaceutical, cosmetic, and food industries, a step towards a green economy.
Contact
Juliana Heloisa Pinê Américo-Pinheiro
Department of Forest Science, Soils and Environment,
School of Agronomic Sciences
São Paulo State University (UNESP)
Ave. Universitária, 3780, Botucatu, SP, 18610-034, Brazil
Email: americo.ju@gmail.com
Reference (open access)
Wani, A.K., Akhtar, N., Mir, T.u.G. et al. Eco-friendly and safe alternatives for the valorization of shrimp farming waste. Environ Sci Pollut Res (2023). https://doi.org/10.1007/s11356-023-27819-z
