POLYGLUTAMIC ACID (γ-PGA)

Aug 31, 2026

γ-Polyglutamic Acid (γ-PGA) is a natural high-molecular-weight polymer produced by microbial metabolism. It was first discovered in the sticky threads of “natto,” a traditional Japanese fermented soybean food, where it accounts for approximately 50–60 % of the viscous substance.

γ-PGA is a linear polymer composed of D‑ and/or L‑glutamic acid units linked by amide bonds between the γ‑carboxyl and α‑amino groups. Its molecular weight typically ranges from 100 to 1,000 kDa, equivalent to about 500–5,000 glutamic acid monomers. The backbone contains a large number of free carboxyl groups, giving γ‑PGA the properties of a water‑soluble polycarboxylic acid.

As a natural, safe, non‑immunogenic, biodegradable, and environmentally friendly biopolymer, γ‑PGA is regarded as a representative “green biopolymer.” It shows broad application prospects in food, cosmetics, pharmaceuticals, agriculture, and environmental protection.

🌿 Natural, Safe, and Biodegradable

γ‑PGA is derived from microbial fermentation and is a natural‑origin biopolymer. It is non‑toxic, edible, highly biocompatible, and can be completely biodegraded into glutamic acid monomers, imposing no burden on the environment. It is an ideal green and sustainable material.

💧 Superb Water Absorption and Moisture Retention

γ‑PGA possesses outstanding water‑absorption and moisture‑retention capabilities. The dense hydrophilic groups in its molecular structure give it powerful water‑binding and‑locking abilities. In cosmetics, γ‑PGA’s moisturising effect is superior to that of hyaluronic acid, with a water‑retention capacity 2–5 times that of sodium hyaluronate.

🧬 Rich Biological Activities

Studies have shown that γ‑PGA exhibits a range of bioactive functions, including promoting mineral absorption, plant growth promotion, immunomodulation, blood‑glucose reduction, and antioxidant activity. It also shows superoxide anion radical scavenging activity and tyrosinase inhibitory activity, demonstrating potential in anti‑ageing and skin‑whitening applications.

🧪 Multifunctionality

γ‑PGA can serve as a thickener, stabiliser, moisturiser, drug carrier, bio‑adhesive, flocculant, and more. Its wide range of uses is rare among biopolymer materials.

Main Application Areas

💄 Cosmetics and Personal Care

γ‑PGA is a star moisturising ingredient in the cosmetics industry. High‑purity γ‑PGA produced by biotechnology forms a protective moisture‑retaining film on the skin and locks moisture from within, offering a novel moisturising function.

Key benefits include:

Superior moisturisation: continuously supplies moisture to the skin, helping to combat dry environments
Improved elasticity: restores skin firmness and smoothes fine lines caused by dehydration
Brightening effect: exhibits certain skin‑lightening properties
Synergistic action: when combined with hyaluronic acid (HA), it effectively prolongs HA’s action time, reduces stickiness, and leaves a naturally smooth feel

γ‑PGA is widely used in face masks, moisturising lotions, serums, eye creams, toners, shampoos, body washes, and other personal care products.

🌾 Agriculture and Soil Improvement

In agriculture, γ‑PGA serves as a novel biostimulant and fertiliser synergist, playing an important role.

Main functions include:

Water and fertiliser retention: with abundant carboxyl groups, γ‑PGA can adsorb water and form gels, with a water‑absorption capacity more than twice that of conventional resins
Soil conditioning: increases porosity in clay soils and improves water retention in sandy soils
Fertiliser efficiency enhancement: improves nutrient utilisation and promotes crop yield
Soil remediation: can be used as a remediation agent for degraded soils

Against the backdrop of global water scarcity and climate change, γ‑PGA, as a non‑toxic, biodegradable green water‑retention material, is seeing growing market demand.

🍽️ Food Industry

γ‑PGA is widely used in the food industry as a thickener, stabiliser, texture modifier, moisturiser, bitterness masker, cryoprotectant for probiotics, and protein crystallisation agent.

Its excellent water‑binding and moisture‑retention properties improve the stability, viscosity, and shelf life of food products, enhance the texture of baked goods, stabilise emulsion systems, and provide anti‑staling protection.

💊 Pharmaceuticals and Biomedical Applications

γ‑PGA shows great potential in the pharmaceutical field. Owing to its excellent biocompatibility, biodegradability, and non‑toxicity, it is extensively studied for:

Drug delivery carriers: as a carrier material for controlled‑release systems
Bio‑adhesives: for tissue engineering and wound repair
Vaccine adjuvants: to enhance immune responses
Gene delivery: as a non‑viral vector for safe gene therapy

♻️ Environmental Protection and Water Treatment

With its outstanding adsorption and flocculation capabilities, γ‑PGA has significant value in environmental protection. It can be used for dye adsorption in printing wastewater treatment and for bio‑flocculation removal of heavy metal ions.

γ‑Polyglutamic acid (γ‑PGA) is a naturally derived, functionally outstanding biopolymer material. From the sticky threads of natto to modern bio‑manufacturing, from a moisturising factor in cosmetics to a green fertiliser synergist in agriculture, γ‑PGA is gradually penetrating every aspect of daily life with its unique advantages of natural safety, biodegradability, superb moisture retention, and multifunctionality.

As a green and sustainable bio‑based material, γ‑PGA not only aligns with the global “carbon peaking and carbon neutrality” goals and the trend towards green development, but also offers new solutions for product upgrading and technological innovation across various industries. With continuous advances in bio‑manufacturing technologies and the ongoing expansion of application fields, γ‑PGA is poised to shine on an even broader stage in the future.