Effect of Sugars on Cell Growth and Lipase Production by Trichosporon cutaneum

Trichosporon cutaneum의 균체생육(菌體生育) 및 Lipase 생산(生産)에 미치는 당류(糖類)의 영향

Inhibitory effect of sugars on lipase production by Trichosporon cutaneum was observed in the previous study (Kim, 1972), and inhibition was distinctive by the addition of glucose, fructose, mannose, xylose and arabinose to the soybean meal medium among various carbon sources. These experiments were carried out to study the effect of sugars on cell growth and lipase production by the strain using the soybean extracts liquid medium under a shaking culture system. Changes in color and pH of the medium were caused by heat sterilization when various sugars were added. To elucidate the possible effect of these coloring matters on lipase production and cell growth: changes in pH of the culture, cell concentration and level of the enzyme activities were determined when the culture was grown for 48 hours at $30^{\circ}C$ on a reciprocal shaker. The results obtained were as follows: 1. Density of brownish color which formed during heat sterilization was varied with the variety of sugar used, ie, strong in pentose such as xylose: weak in hexose such as galactose, mannose, glucose: very weak in disaccharide such as maltose, sucrose. When the color density was stronger, decrease in pH after sterilization was marked. 2. Cell growth and lipase production was not so effect by the coloring matters as by sugars. 3. The more the cell mass of the culture, the lower the level of lipase production in the culture supernatant. 4. Among the sugars which caused the distinctive inhibition of lipase production, a slight relief of inhibition was noticed by the addition of xylose, whereas the cell growth was repressed. 5. When cell growth was better, decrease in pH of the medium was greater during cultivation.

전보(前報)에 이어 Trichosporon cutaneum의 lipase 생산(生産)에 미치는 당류(糖類)의 영향을 더욱 검토(檢討)하기 위(爲)하여 몇가지 당류(糖類)를 첨가(添加)한 대두분추출액(大豆粉抽出液) 기본배지(基本培地)를 151bs에서 20분간(分間) 살균(殺菌)하였을때 일어나는 pH 및 착색도변화(着色度變化), 착색물질(着色物質)이 균체(菌體)의 생육(生育) 및 lipase 생산(生産)에 미치는 영향, 그리고 $30^{\circ}C$에서 진탕 배양(培養)하면서 배양중(培養中)의 pH 변화(變化)와 균체(菌體)의 생육(生育) 및 lipase 생산(生産)과의 관계(關係)를 검토(檢討)하여 아래와 같은 결과(結果)를 얻었다. 1. 대두분추출액(大豆粉抽出液) 기본배지(基本培地)에 각중당류(各種糖類)를 첨가(添加)하여 살균(殺菌)하였을 때 일어나는 갈변(褐變)은 xylose 첨가구(添加區)가 가장 심(甚)하고 다음이 galactose와 mannose, glucose 첨가구(添加區)의 순(順)이 었고 maltose와 sucrose 첨가구(添加區)는 당무첨가구(糖無添加區)와 별차이(別差異)가 없었다. 2. 살균후(殺菌後)에 갈변(褐變)이 심(甚)한 것일수록 pH가 낮았다. 3. 살균중(殺菌中)에 형성(形成)된 착색물질(着色物質)은 당(糖)의 종류(種類)에 비(比)하여 균체(菌體)의 생육(生育)및 lipase 생산(生産)에 미치는 영향이 작았다. 4. lipase 생산량(生産量)이 많을수록 균체(菌體)의 생산량(生産量)이이 작았다. 5. 살균중(殺菌中)의 갈변(褐變)이 가장 심(甚)한 xylose 첨가구(添加區)에서는 균체(菌體)의 증식(增殖) 및 lipase 생산저해작용(生産沮害作用)이 약천(若千) 약화(弱化)되었다. 6. 균체(菌體)의 증식(增殖)이 왕성(旺盛)할수록 배지(培地)의 pH가 낮아졌다.