ε-聚離胺酸（ε-Poly-lysine；ε-PL）是由微生物發酵生產的天然生物性材料。ε-PL具有水溶、可食及生物可分解等特性且其本身或分解之產物對人體及環境不具毒性。由於具極佳的抑菌活性，水溶性強，熱穩定性高，食用安全，添加微量即能奏效，又不影響風味，因此在食品防腐領域得到廣泛應用。本研究使用我們自己實驗室從野外篩選的一株有潛力生產ε-PL的菌株Streptomyces albulus DYU 1，實驗證明該菌株可利用甘油為碳源。以甘油為碳源，用二階段式發酵培養S. albulus DYU 1，並以一次一因子之方式探討在第二階段生產培養基生產ε-PL之最適化，結果發現對生產ε-PL影響最大的是 (NH4)2SO4，其次是甘油，環境因子部分則是pH值具有明顯的影響，目前發現最適培養條件為第一階段培養應選擇24~36小時較為適合，而在第二階段培養為甘油 25 g/L、(NH4)2SO4 10 g/L和L-lysine 1.6 g/L，在此條件下S. albulus DYU 1 於30℃、160 rpm培養六天後可生產約 1.4 g/L~1.6 g/L的-PL。本研究發現S. albulus DYU 1可利用甘油生產生物可分解高分子-PL，因此將來應有潛力應用至廢甘油之轉換，以提高生質柴油副產物甘油之經濟價值，同時解決廢甘油衍生之環保問題。

ε-Poly-lysine (ε-PL) is a naturally-occurring bio-material produced by microbial fermentation. It is water soluble, biodegradable, edible, and nontoxic to humans and the environment. ε-PL shows a wide range of antimicrobial activity, and it is stable at high temperatures. Because it is effective in trace amounts and has no taste, it is widely used as a food preservative. In this study, we investigated the production of ε-PL by Streptomyces albulus DYU 1, a strain isolated in our lab and having high potential for ε-PL production, by using glycerol as the sole carbon source in two-stage culture fermentation. In our investigation of the effects of carbon and nitrogen sources on ε-PL production, we found that (NH4)2SO4 significantly affected ε-PL production; in addition, pH also exhibited a significant effect. We also determined that cultivating the strain for 24–36 h at the first stage and cultivating it in glycerol 25 g/L, (NH4)2SO4 10 g/L, and L-lysine 1.6 g/L at the second stage represented optimal culture conditions. In this medium, S. albulus DYU 1 produced -PL at 1.4 g/L to 1.6 g/L postincubation at 30 °C and 160 rpm for 6 days at the second stage of cultivation. Our results illustrate that S. albulus DYU 1 is capable of converting glycerol into ε-PL, a versatile biopolymer. The conversion of glycerol into valuable products not only enhances the value of biodiesel production but may also solve the environmental problem of glycerol waste.