The environmental advantages and sustainable development of Nisin

Against the backdrop of the food industry’s transition toward "green and low-carbon" practices, traditional chemical preservatives (e.g., sodium benzoate, potassium sorbate) face growing concerns regarding environmental residue risks and high energy consumption in production. In contrast, Nisin (lactococcal bacteriocin), a natural antimicrobial peptide produced by the fermentation of Streptococcus lactis, has emerged as an ideal food preservation solution aligned with sustainable development principles, thanks to its core advantages of "biogenic origin, environmental compatibility, and low-carbon production." A systematic analysis of Nisin’s eco-friendly properties across its entire life cycle (production, application, and degradation), combined with its practical value in the circular economy, clarifies its role in advancing the sustainable development of the food industry while providing directions for future technological optimization.

I. Eco-Friendly Advantages: Environmentally Friendly Traits Across the Entire Life Cycle

Nisin’s eco-friendly advantages span the entire "production-application-waste" life cycle, reducing resource consumption and pollution emissions at the source—addressing the shortcomings of traditional chemical preservatives, such as "high carbon footprint and poor degradability." These advantages are evident in three dimensions:

(I) Production Process: Low-Carbon Fermentation with High Resource Efficiency

Nisin production relies on microbial fermentation, leveraging the biotransformation of carbohydrates by Streptococcus lactis. Compared to the chemical synthesis of preservatives, this process offers significant low-carbon and resource-saving benefits:

Renewable raw materials reduce fossil resource dependence: Fermentation feedstocks primarily include renewable biomass such as corn starch, sucrose, and whey, eliminating the need for non-renewable fossil resources like petroleum and coal. For example, producing 1 ton of Nisin consumes approximately 800 kg of corn starch, whereas manufacturing an equivalent output of sodium benzoate requires about 600 kg of petroleum derivatives (e.g., toluene). Additionally, sodium benzoate synthesis uses strong acids (e.g., nitric acid) and alkalis (e.g., sodium hydroxide), generating acid-alkali wastewater. The renewability of Nisin’s feedstocks not only reduces reliance on fossil resources but also minimizes ecological damage from raw material extraction (e.g., soil pollution and marine spills from oil drilling).

Low energy consumption and reduced carbon emissions: Fermentation occurs at moderate temperatures (30–32°C) and atmospheric pressure, avoiding high-temperature and high-pressure reaction conditions. Comparative data shows that the comprehensive energy consumption for producing 1 ton of Nisin is approximately 2,000 kWh, with carbon emissions of around 1.2 tons of CO₂ equivalent. In contrast, sodium benzoate production requires 5,000 kWh of comprehensive energy per ton and emits 3.5 tons of CO₂ equivalent—meaning Nisin production reduces energy consumption and carbon emissions by over 60% and 65%, respectively. Moreover, waste heat from fermentation can be recovered for workshop heating, further minimizing energy waste and aligning with "low-carbon manufacturing" principles.

Recyclable by-products minimize waste discharge: After extracting and purifying Nisin from fermentation broth, the resulting bacterial residue—rich in protein (40%–50% content)—can be used as a feed additive (e.g., for livestock and aquaculture), achieving "waste resource utilization." In contrast, waste residues from chemical preservative production (e.g., salts, unreacted raw materials) are mostly hazardous waste requiring specialized treatment (e.g., incineration, landfilling), which easily contaminates soil and groundwater. For instance, salt-containing wastewater from sodium benzoate production raises water salinity and disrupts aquatic ecosystems if discharged directly. Nisin’s bacterial residue, however, has a resource utilization rate of over 90%, essentially achieving "zero solid waste" discharge.

(II) Application Stage: Low-Dosage Efficacy Reduces Environmental Residue Risks

Nisin’s application characteristics in food processing further minimize its potential environmental impact, with core advantages of "low addition levels, targeted antimicrobial activity, and no residual accumulation":

Ultra-low addition levels reduce environmental input: Nisin exhibits strong inhibitory activity against Gram-positive bacteria (e.g., Clostridium botulinum, Listeria monocytogenes), requiring only 0.01–0.2 g/kg (10–200 mg/kg) in food—far lower than chemical preservatives (e.g., sodium benzoate has a maximum allowable addition level of 1 g/kg). Low addition levels significantly reduce the "total preservative input" into the environment during food processing. For example, a dairy enterprise producing 100,000 tons of dairy products annually uses approximately 1 kg of Nisin as a preservative, compared to 100 kg of sodium benzoate—reducing Nisin’s environmental input by 99% and minimizing preservative release from incineration or landfilling of food waste (e.g., expired products).

Targeted antimicrobial activity preserves environmental microbial communities: Nisin only damages the cell membranes of Gram-positive bacteria and does not inhibit beneficial microorganisms in the environment (e.g., nitrogen-fixing bacteria in soil, photosynthetic bacteria in water) or human gut microbiota. In contrast, chemical preservatives (e.g., potassium sorbate) have a broad antimicrobial spectrum, easily accumulate in the environment, inhibit microbial activity in soil or water, and disrupt ecological balance. For instance, food waste containing potassium sorbate mixed into farmland reduces soil microbial counts by 20%–30%, impairing soil fertility. Nisin-containing food waste, however, does not significantly alter microbial community structure, offering higher ecological safety.

No chemical residues avoid bioaccumulation: As a polypeptide, Nisin is degraded into amino acids by proteases in the human digestive tract, with no in vivo accumulation. When released into the environment, it is rapidly degraded by microorganisms in soil or water (half-life: ~2–3 days), posing no risks of long-term residues or bioaccumulation. In contrast, chemical preservatives (e.g., parabens) are lipid-soluble, easily accumulate in aquatic organisms (e.g., fish, shellfish), and affect higher organisms via the food chain—even potentially disrupting the endocrine system. Multiple environmental toxicology studies confirm that Nisin degrades completely in natural environments, with no bioaccumulation and almost zero potential risk to ecosystems.

(III) Waste Stage: Easy Degradation Prevents Persistent Environmental Pollution

After food disposal, the degradability of Nisin-containing residues in the environment further highlights its eco-friendly advantages, avoiding the "persistent pollution" issue of traditional preservatives:

High biodegradability with no accumulation in environmental media: Nisin is a polypeptide composed of 34 amino acids. In soil, water, or compost environments, it is rapidly hydrolyzed into small-molecule amino acids by microbially secreted proteases (e.g., peptidases, proteinase K), eventually converting into CO₂, H₂O, and nitrogen-containing inorganic substances (e.g., NH₄⁺, NO₃⁻) that re-enter the natural material cycle. Experimental data shows that Nisin achieves over 95% degradation in soil within 7 days, whereas sodium benzoate only degrades 30%–40% in the same period—with some seeping into groundwater and causing long-term pollution.

Composting promotes degradation and enhances organic waste value: When Nisin-containing food waste (e.g., expired dairy products, meat products) undergoes composting, Nisin degradation does not inhibit the activity of compost microorganisms (e.g., actinomycetes, yeast). Instead, its degradation products (amino acids) serve as nitrogen sources for microorganisms, accelerating compost maturation. Comparative experiments show that composting food waste with Nisin shortens maturation time by 5–7 days (vs. sodium benzoate), increases organic matter content in the final compost by 5%–8%, and contains no preservative residues—making it safe for farmland fertilization and enabling the circular "food waste → compost → farmland" cycle.

II. Practical Pathways to Advance Sustainable Development in the Food Industry

Nisin’s eco-friendly advantages extend beyond its inherent properties; it drives full-chain sustainable development in the food industry through three key pathways—"replacing chemical preservatives, optimizing processing technologies, and supporting the circular economy"—addressing industry pain points of "high pollution, high energy consumption, and resource waste."

(I) Replacing Chemical Preservatives to Reduce the Food Industry’s "Environmental Footprint"

The food industry is the primary user of chemical preservatives. Large-scale Nisin application significantly reduces the industry’s environmental burden:

Reducing pollution emissions at the production end: In the dairy industry, for example, China produces approximately 30 million tons of dairy products annually. If Nisin fully replaces sodium benzoate as a preservative, annual sodium benzoate usage would decrease by ~300 tons, reducing petroleum derivative (toluene) consumption by ~180 tons and cutting CO₂ emissions from chemical production by ~1,050 tons (based on 3.5 tons of CO₂ per ton of sodium benzoate). Additionally, it would reduce acid-alkali wastewater discharge from chemical preservative production by ~5,000 tons, lowering sewage treatment costs.

Minimizing environmental risks at the consumption end: In the meat industry, Nisin can replace nitrites (traditional preservatives and color fixatives in meat products). Nitrites easily convert into carcinogenic nitrosamines in the environment and cause eutrophication (e.g., cyanobacterial blooms) when over-discharged. Nisin, however, requires only 0.05–0.1 g/kg in meat products and poses no nitrosamine risk. China produces ~15 million tons of meat products annually; if 50% of these use Nisin instead of nitrites, annual nitrite emissions would decrease by ~750 tons, significantly reducing water eutrophication risks and protecting aquatic ecosystems.

(II) Optimizing Food Processing Technologies to Achieve "Bacteria Reduction-Energy Savings" Synergy

Nisin’s antimicrobial activity synergizes with low-intensity thermal processing, reducing energy consumption and nutrient loss in food processing—aligning with "green processing" principles:

Lowering thermal processing intensity to save energy: Traditional food sterilization requires high-temperature, long-duration treatment (e.g., 121°C for 20 minutes) to kill heat-resistant spores. With Nisin, sterilization temperatures can drop to 105–110°C and durations shorten to 5–10 minutes. For example, in canned pea processing, adding 0.1 g/kg Nisin reduces the sterilization temperature from 121°C to 105°C, cutting steam consumption per ton of cans by 30%. For a 10,000-ton canned food facility, this saves ~100 tons of standard coal annually. Meanwhile, low-intensity thermal processing reduces losses of heat-sensitive nutrients (e.g., vitamin C, B vitamins) from 30% to below 10%, improving food nutritional value and minimizing "nutrient waste."

Extending food shelf life to reduce food waste: Food waste is a critical global sustainability challenge. The Food and Agriculture Organization (FAO) estimates that ~1/3 of global food is wasted during production and consumption; this waste not only squanders resources but also generates methane (a potent greenhouse gas) in landfills. Nisin inhibits spoilage bacteria, significantly extending food shelf life. For example, adding 0.03 g/kg Nisin to fresh milk lengthens its shelf life from 7 days to 21 days, reducing waste from expiration. China produces ~40 million tons of fresh milk annually; a 5% waste reduction via Nisin application saves 2 million tons of milk yearly, reducing associated feed and water consumption (1 ton of milk requires ~10 tons of water and 4 tons of feed) and indirectly alleviating environmental pressure from agricultural production.

(III) Supporting the Circular Economy in the Food Industry to Improve Resource Efficiency

Nisin’s production and application integrate into the food industry’s circular economy system, creating a closed loop of "resources → products → waste → recycled resources":

Recycling fermentation by-products to link food-feed value chains: As noted earlier, Nisin fermentation residues—rich in protein—serve as protein sources for livestock and aquaculture feed. China produces ~500 tons of Nisin annually, generating ~2,000 tons of bacterial residues that can replace ~1,500 tons of soybean meal (a traditional feed protein source). This reduces dependence on imported soybean meal (China imports ~100 million tons annually) and lowers land and water consumption for soybean meal production (growing 1 ton of soybeans requires ~2,000 tons of water).

Promoting food waste composting to link food-agriculture cycles: Nisin-containing food waste (e.g., expired dairy, meat) is more suitable for composting due to the absence of chemical preservative residues. For example, expired milk from dairy enterprises—treated with Nisin—can be directly composted. The resulting compost contains ~2%–3% nitrogen and ~40% organic matter, which can be reused for corn cultivation (a feedstock for Nisin fermentation). This forms a circular chain of "corn cultivation → milk production → Nisin application → expired milk composting → corn cultivation," reducing chemical fertilizer use (compost replaces ~30% of chemical nitrogen fertilizer) and mitigating agricultural non-point source pollution (fertilizer runoff is a major cause of water eutrophication).

III. Challenges and Future Directions in Sustainable Development Research

Despite Nisin’s significant advantages in environmental protection and sustainability, its large-scale application faces technical bottlenecks. Future research should focus on the following areas to further enhance its sustainability:

(I) Current Challenges: Constraints from Production Efficiency and Application Costs

Low fermentation efficiency and high raw material consumption: Current Nisin fermentation titer is ~5,000–8,000 IU/mL, much lower than other fermented products (e.g., penicillin titer reaches 100,000 IU/mL). This leads to high raw material (corn starch) consumption and production costs—3–5 times higher than chemical preservatives—limiting its use in mid-to-low-end food products.

Insufficient application stability requiring additives: Nisin is stable in acidic environments (pH < 5) but degrades easily in neutral or alkaline conditions (e.g., meat, soy products). Stabilizers (e.g., β-cyclodextrin, trehalose) are required, increasing application costs and environmental input (some stabilizers are poorly degradable).

Lack of recycling technology: No effective technology exists to recover excess Nisin added during food processing. This leads to partial Nisin discharge with wastewater; although degradable, it still wastes resources.

(II) Future Research Directions: Technological Innovation to Enhance Sustainability

Strain modification and fermentation process optimization: Use genetic engineering to modify Streptococcus lactis (e.g., knocking out acid-producing genes, enhancing Nisin synthetase activity) to increase fermentation titer to over 15,000 IU/mL and reduce raw material consumption. Develop "high-concentration substrate fermentation" technology to reduce fermentation broth volume, lowering energy consumption and wastewater discharge during subsequent extraction and purification.

Development of green stabilizers: Research biodegradable natural stabilizers (e.g., plant polysaccharides, chitosan) to replace chemical stabilizers, improving Nisin stability in neutral/alkaline foods while ensuring co-degradation with Nisin and no environmental residues.

Nisin recovery and recycling: Develop "adsorption-desorption" technologies (e.g., using porous biomass adsorbents) to recover Nisin from food processing wastewater. After purification, it can be reused for food preservation, achieving Nisin recycling and further reducing resource consumption.

Cross-industry collaborative application: Explore Nisin applications in agriculture (e.g., fruit and vegetable preservation) and medicine (e.g., natural antimicrobials) to expand market scale and lower costs via mass production. Promote "food-Nisin-agriculture" cross-industry cycles—for example, using Nisin to preserve fruits and vegetables (reducing waste) and repurposing expired fruits/vegetables as Nisin fermentation feedstocks—creating a broader circular economy system.

As a natural biological preservative, Nisin’s eco-friendly advantages—"low-carbon production, environmental compatibility, and easy degradation"—not only address the environmental residue and high carbon footprint issues of traditional chemical preservatives but also drive the food industry’s transition to a "green, low-carbon, circular" sustainable development model through replacing chemical preservatives, optimizing processing technologies, and supporting the circular economy. Despite current challenges of low fermentation efficiency and high costs, technological innovations such as strain modification, process optimization, and cross-industry collaboration will position Nisin as a core enabler of sustainable development in the food industry. It will provide a critical technical pathway for the food sector’s transition under "dual carbon" goals (carbon peaking and carbon neutrality) while contributing to global food safety and ecological environmental protection.