담수조류 그물말로부터 당 용액의 효율적 제조를 위한 가수분해 방법

Abstract

담수조류인 그물말 (Hydrodictyon reticulatum, HR)의 실용적 당화조건 확립을 위해 산 가수분해 방법으로서 one-step acid hydrolysis과 two-step acid hydrolysis, 그리고 산가수분해 후 효소가수분해를 병행하는 combined hydrolysis를 검토하였다. One-step acid hydrolysis의 경우, <TEX>$120^{\circ}C$</TEX>에서 HR 4% 고형분을 2% 황산 용액에 넣어 1시간 동안 반응시킬 경우가 적정하였다. Two-step acid hydrolysis의 적정조건은 1차 가수분해시 HR 건조중: 72% 황산을 1 g : 1.5mL로 하여 <TEX>$60^{\circ}C$</TEX>에서 1시간 반응시킨 다음, 증류수 23.5 mL를 첨가하고 <TEX>$120^{\circ}C$</TEX>에서 1시간 가수분해시키는 것이었다. Combined hydrolysis의 경우, 2% 염산에 25%의 HR 고형분을 넣고 <TEX>$120^{\circ}C$</TEX>에서 1시간 반응시킨 후, citrate buffer로 4% 고형분 함량이 되도록 희석하고 E1+E2 효소를 각각 1+0.2 mL g <TEX>$DM^{-1}$</TEX> 수준으로 첨가하여 <TEX>$50^{\circ}C$</TEX>에서 1~2일 동안 반응시키는 것이 바람직하였다. Glucose 생성량, 발효억제물질(HMF, furfural) 생성량, 강산 사용제한 등을 종합적으로 감안할 때, combined hydolysis가 보다 유용할 것으로 판단되었다. To explore hydrolysis methods for the efficient manufacture of sugar solutions from the freshwater alga Water-net (Hydrodictyon reticulatum, HR), acid hydrolysis, enzymatic hydrolysis, and combined hydrolysis (acid followed by enzymatic hydrolysis) were investigated. In the one-step acid hydrolysis, the reaction of 8% solids content using 2% sulfuric acid at <TEX>$120^{\circ}C$</TEX> for 1 hour was desirable. In this case, glucose 27.44 g 100 g <TEX>$DM^{-1}$</TEX> could be obtained from the HR-d13 samples. In the two-step acid hydrolysis, the primary hydrolysis (HR powder : 72% sulfuric acid = 1 g : 1.5 mL) was carried out for 1 hour at <TEX>$60^{\circ}C$</TEX>, and then the secondary hydrolysis was done for 1 hour at <TEX>$120^{\circ}C$</TEX> after addition of distilled water 23.5 mL. In this case, glucose 35.11 g/100 g DM could be obtained from the HR-d13 samples. In the combined hydrolysis, 25% solids content using 2% hydrochloric acid were reacted for 1 hour at <TEX>$120^{\circ}C$</TEX>, and then citrate buffer and hydrolysis enzyme complexes (E1 1.0 mL+E2 0.2 mL <TEX>$g^{-1}$</TEX> dried matter) were added and reacted for 1 - 2 days at <TEX>$50^{\circ}C$</TEX>. In this case, glucose 33.5 g 100 g <TEX>$DM^{-1}$</TEX> could be obtained from the HR-d23+26 samples. In conclusion, combined hydrolysis was likely to be more useful saccharification method of HR biomass at a practical level, considering the glucose productivity, generation of fermentation-inhibiting substances (hydroxyl methyl furfural, furfural), and limited use of strong acid.