PLA vs PBS — Choosing the Right Biodegradable Bag for Your Brand

When customers ask us for "a biodegradable bag," they usually mean one of two things — a bag with a **PLA** lining or a bag with a **PBS** lining. The names sound similar, but the materials behave differently in real-world use, and the right choice depends on what you're packing and where the bag will end up after use. ## PLA — corn-based, industrially compostable **PLA (polylactic acid)** is made from fermented plant starch — usually corn. It's the more common of the two and is what most people picture when they hear "bioplastic." **Strengths** - Clear, glossy finish. Looks crisp on a shelf. - Dry-goods friendly — bakery, dry tea, apparel, gift. - Widely available, predictable pricing. **Limitations** - **Industrial composting only.** PLA needs ~60 °C and humidity to break down within 90–180 days. It will *not* meaningfully degrade in a backyard compost or landfill. - Not heat-resistant — softens above 50 °C. - Brittleness can be an issue for heavy contents. PLA is the right answer when your customers are likely to dispose of the bag through a municipal composting program, or when "compostable" is a brand claim you can defend with the right disposal language. ## PBS — petrochemical-based, marine-degradable **PBS (polybutylene succinate)** is more recent and behaves quite differently. Despite often being made from petrochemical feedstock, it degrades faster and in a wider range of environments — including marine water and home compost. **Strengths** - **Home-compostable** at standard ambient conditions (varies by formulation). - Heat-tolerant up to ~80 °C — better for warm or humid contents. - More flexible and tear-resistant than PLA. - Marine-degradable formulations exist (relevant for coastal markets). **Limitations** - Less optical clarity — slight haze. - 10–20% higher material cost than PLA, depending on order size. - Smaller global supply base. PBS is the better answer for warm-fill foods, fresh produce, flowers, or projects in coastal markets where stricter "marine-safe" claims are valuable. ## How to decide in 30 seconds | Use case | Pick | |---|---| | Bakery, retail, gift, apparel — composted via municipal facility | **PLA** | | Hot drinks, warm bakery, prepared food, flowers | **PBS** | | Coastal market with marine-degradable claims | **PBS** | | Lowest cost, dry-goods only | **PLA** | | Backyard / home compost certification needed | **PBS** | ## What we ship at Starmi We stock both. A typical custom run: - **PLA bag**: 4–6 days for a sample, 10–12 days for production at 5,000 pcs. - **PBS bag**: 5–7 days for a sample, 12–14 days for production at 5,000 pcs. If you're not sure which fits, [send us your use case](/inquiry) — describe what's going in the bag, where customers will dispose of it, and any sustainability claims you want to make on-pack. We'll come back with a side-by-side comparison and a sample of each.