利用黏紅酵母發酵鳳梨皮廢液產生生物界面活性劑之物理性質研究

生物界面活性劑泛指生物來源的界面活性化合物，其來源通常泛指是微生物(細菌、酵母菌、真菌)胞外產生的界面活性物質，生物界面活性劑具有許多環境的應用，如生物降解性、低(無)毒性、環境友善性質。本研究是利用高油脂黏紅酵母菌Rhodotorula glutinis BCRC 22360進行農業廢棄物-鳳梨皮廢汁液的發酵，並進行發酵時間(Ft)(0、2、4、6、8、10、12、24、36、48小時)對其發酵上清液所含生物界面活性劑之乳化指數及表面張力性質探討。另外，將最佳生長狀態的黏紅酵母接菌至鳳梨皮廢汁液進行發酵培養，在適當發酵時間進行發酵液取樣，然後將發酵液樣品進行離心取上清液，並將上清液分為高溫高壓滅菌以及無滅菌兩部分，並進行發酵上清液(SNs)之乳化穩定性及表面張力測定。由實驗結果得知，滅菌與無滅菌SNs之乳化指數分別在前4小時與前8小時Ft會隨著發酵時間增加而下降，然後其乳化指數即隨著發酵時間增加而上升。滅菌後SNs之表面張力在前2小時Ft會隨著發酵時間增加而先行下降，在2~6小時Ft中其表面張力隨著發酵時間增加而增加，但在8小時Ft後其表面張力即隨著發酵時間增加而下降；無滅菌SNs之表面張力在前8小時則隨著發酵時間增加而增加，而後其表面張力即隨著發酵時間增加而下降。分別在24、36、48小時取樣SNs，將經滅菌或無滅菌處理後SNs進行稀釋倍數對其乳化指數及表面張力影響之測試，由實驗結果得知，SNs之乳化指數會隨著稀釋倍數增加而下降，但其SNs之表面張力則呈現上升。在48小時Ft所得滅菌後SNs儲存在室溫下，其乳化指數雖然略微低於相同Ft所得無滅菌SNs之指數，但儲存第2週後之滅菌後SNs乳化穩定性則優於無滅菌SNs。本研究結果顯示，利用黏紅酵母R. glutinis BCRC 22360發酵鳳梨皮廢液所產生生物界面活性劑是值得在如環保、食品、未來生物醫藥、化妝品及醫藥等行業開發及應用。

關鍵字

生物界面活性劑；黏紅酵母菌；鳳梨皮汁液；乳化指數；表面張力

並列摘要

Biosurfactants, ones of surface-active compounds from biological sources, usually extracellular produced by microorganisms (bacteria, yeasts or fungi), have many environmental applications such as bioremediation and low- or non-toxicity, environmentally friendly nature. The emulsification and surface tension properties of biosurfactants produced from waste liquid of pineapple peel fermented by the oleaginous yeast Rhodotorula glutinis BCRC 22360 were investigated in this study. The effects of fermentation time (Ft) (0, 2, 4, 6, 8, 10, 12, 24, 36, 48 hrs) on the properties of the biosurfactants from the sterilized and unsterilized cell-free fermented supernatants (defined as SSNs and USNs, respectively) were also investigated. The emulsification indices (EIs) of SSNs and USNs decreased at the first 4 hrs and 8 hrs of Ft, respectively, and then they increased thereafter. The surface tension (ST) values of SSNs at first 2 hrs Ft decreased, and the values of those increased during 2~6 hrs Ft and then gradually decreased after 8 hrs Ft. The ST values of the USNs increased at first 8 hrs Ft and then they decreased thereafter. The EIs and ST values of SSNs and USNs obtained at 24, 36, 48 hrs Ft were decreased and increased, respectively, with increasing dilution fold. However, the EI values of SSNs at 48 hrs Ft after the 2nd week of storage at room temperature were little lower but more stable than those of USNs at 48 hrs after the same storage time. Therefore, this study demonstrated that the biosurfactants produced from waste liquid of pineapple peel fermented by R. glutinis BCRC 22360 are worth to developing the impending applications in a variety of industries such as environmental, food, biomedical, cosmetic and pharmaceutical industries in the future.