|Abstract: ||摘 要 菌株 Micrococcus sp. strain DB05B 為分離自附著於浸漬海水中材料片之海洋黏性菌株，由實驗結果顯示於 26oC、150 rpm 振盪培養 48小時下，當以 5% 乳糖與 0.71% yeast extract 取代黏液篩選基礎培養基 (mucous screening basal broth, MSBB) 中之碳源與氮源時，可使胞外黏性物質 (extracellular adhesive substance, EAS) 的產量由 0.29-0.31 g/L 分別提高至 0.74 g/L 與 0.65 g/L。當添加 10 ppm 的 Mn+2 離子與 1.5 mM disodium-β-glycerophosphate (DSGP) 於 MSBB 中，分別可獲得較高的 EAS 產量 (0.57 與 0.68 g/L)。在培養條件方面，經測試在不同起始 pH 值、培養溫度、振盪培養轉速後，可得到最適生產 EAS 之個別條件為：起始 pH 值為 7.2、培養溫度為 26oC、振盪培養轉速為 150 rpm，其 EAS 產量可提升至 0.80-0.85 g/L。將最佳生產條件與培養基組成綜合成為菌株 DB05B 之乳糖修飾黏液產生培養液 (modified-mucous production broth-lactose, M-MPB-L)。添加幾丁質片、活性碳片、小木塊、玻璃珠、聚丙烯珠及小鋼珠等六種不同材質於 M-MPB-L 中培養菌株 DB05B，加入幾丁質片組可獲得較高之 EAS 產量 (0.89 ± 0.02 g/L)，其次為活性碳片 (0.77 ± 0.21 g/L)。菌株 DB05B 於 MSBB 及 M-MPB-L 所產 EAS 之組成成分中水分分別為 10.8% 和 10.9%、醣量分別為 60.8% 和 63.4%、與蛋白質含量 14.8% 和 18.3%。EAS 凍乾粉末復水溶液的相對黏度 (relative viscosity, RV) 隨所添加 EAS 濃度增加而增高，但當溶液中另外添加 0.1-0.5% NaCl 時，則該 EAS 溶液 RV 隨 NaCl 濃度之增加，則呈現下降的趨勢。0.2% EAS 復水溶液之 RV 隨著溫度的上升 (10-80oC) 而遞減。測定 0.2% EAS 復水溶液於 pH 2.0-10.0 的 RV 時，發現 pH 2.0 時有較高的相對黏度表現 (RV = 1.19)。將菌株 DB05B 所生產的 EAS 凍乾粉末加入分離大豆蛋白質溶液中時，當 EAS 的濃度在 0.0-1.0% 時，其乳化活性為 37%-42%，乳化安定性為 21%-40%。1.0-2.0% 菌株 DB05B 所產 EAS 復水溶液皆具成膜性，以 2.0% EAS 形成的膜韌性較佳。菌株 DB05B 於 MSBB 和 M-MPB-L 培養液中所得之 EAS，以 5、10、15 mg/mL 三種濃度測試其抗氧化能力，在抑制血紅素催化亞麻油酸自氧化能力方面，以 MSBB 培養所得 EAS 較 M-MPB-L 為佳。於 MSBB、M-MPB-L 培養液中所得之 EAS （15 mg/mL） 分別有 6.70 ± 0.01% 與 3.56 ± 0.00% 清除 DPPH 自由基能力。在螯合亞鐵離子能力方面，於 MSBB 和 M-MPB-L 培養液中所得之 EAS （15 mg/mL） 分別有 93.46 ± 0.08% 和 56.33 ± 1.11% 的表現。|
Abstract Micrococcus sp. strain DB05B was isolated from the biofouling material suspended in sea water. While 5% lactose and 0.71% yeast extract were used to replacing the carbon source and nitrogen source of mucous screening basal broth (MSBB), the results indicated that the extracellular adhesive substance (EAS) yields were increased from 0.29-0.31 g/L up to 0.74 g/L and 0.65 g/L, respectively. Ten ppm Mn2+ metal or 1.5 mM disodium-β-glycerophosphate (DSGP) was added into the MSBB individually, and then higher EAS yields, 0.57 and 0.68 g/L were achieved, respectively. Modified-mucous production broth-lactose (M-MPB-L) is composed of the individual best cultured medium ingredient for strain DB05B. The effect of culture conditions were examined individual, the results showed that while the initial pH at 7.2, incubation temperature at 26oC, and shaking speed with 150 rpm, the highest EAS yields of 0.80-0.85 g/L could be reached in each condition tested. The effect of different substrata, such as activated carbon flake, chitin flake, wood piece, stainless steel beads, glass beads, or polypropylene beads, on the EAS yield produced from strain DB05B were also investigated. The chitin flake added to M-MPB-L performed the highest EAS yield, as 0.89 ± 0.02 g/L, as compared to other testing substrata, the second for EAS yield was activated carbon flake, which obtained 0.77 ± 0.21 g/L. The compositions of EAS lyophilized powders that obtained from strain DB05B culturing with the MSBB or M-MPB-L had moisture content as 10.8% and 10.9%, carbohydrate content as 60.8% and 63.4%, and protein content as 14.8% and 18.3%, respectively. The relative viscosity (RV) of EAS rehydrated aqueous solution was increased while the concentration of EAS was increased in the reacting solution. However, EAS solution with the addition of increasing NaCl concentration from 0.0%-5.0% were performed lower RV. The RV of 0.2% lyophilized EAS powder rehydrated solution was increasing while reacting temperature (10-80oC) were decreased. The 0.2% lyophilized EAS powder rehydrated solution showed the higher RV while the pH of reacting solution was adjusted to 2.0 than it did in other adjusted pH value (3.0-10.0). Effect of EAS addition on emulsifying activity and emulsion stability while mixed with isolated soy protein, the result showed that emulsifying activities of 0.0-1.0% EAS were ranged from 37% to 42%, and their emulsion stabilities were ranged from 21% to 40%. The 1.0-2.0% EAS rehydrated solution performed the capability of film formation. The EAS recovered from the cultivation of strain DB05B in MSBB or M-MPB-L were used to test for their capability on antioxidation in the concentration ranged from 5 to 15 mg/mL. The ability for inhibition of hemoglobin catalyzing linoleic acid was examined, the lyophilized EAS derived from MSBB showed a better result than the EAS derived from M-MPB-L. While the ability for scavenging DPPH free radical was examined, the lyophilized EAS obtained from MSBB (15 mg/mL) or M-MPB-L (15 mg/mL) performed antioxidative activity as 6.70 ± 0.01% and 3.56 ± 0.00%, respectively. For evaluating their antioxidation effect, lyophilized EAS obtained from MSBB (15 mg/mL) or M-MPB-L (15 mg/mL) presented 93.46 ± 0.08% and 56.33 ± 1.11% capability on the chelating Fe2+ ion, respectively.