Ho-Yong Kim

Optimization of enzymatic hydrolysis conditions for extraction of pectin from rapeseed cake (Brassica napus L.) using commercial enzymes.

The aims of this study were to extract pectin from rapeseed cake (RSC) by enzymatic hydrolysis using commercial enzymes (Celluclast and Alcalase) and to investigate the effects of different reaction conditions, such as enzymatic hydrolysis time, enzyme-RSC ratio, and Celluclast-Alcalase ratio, on the degradation of RSC and pectin yield. RSC was treated using a combined extraction process that consisted of a fat removal process, enzymatic hydrolysis, and isopropanol/ethanol precipitation. After the fat removal process and enzymatic hydrolysis, defatted-RSC was suitably decomposed, and the loss of liberated reducing sugars was minimized when the hydrolysis condition reached a hydrolysis time of 270 min or an enzyme-RSC ratio of 1:50. Based on these results, various Celluclast-Alcalase ratios were applied. Alcalase led to the destruction of protein-carbohydrate complex in defatted-RSC, whereas Celluclast cleaved some linkages of carbohydrate slightly. As a result, the highest pectin yield was 6.85% at the Celluclast-Alcalase ratio of 1:4.

Efficacy of wood preservatives formulated from okara with copper and/or boron salts

As a substitute for high-cost copper azole (CuAz) and alkaline copper quaternary (ACQ) wood preservatives, alternative wood preservatives were formulated with okara, which is an organic waste from the production of tofu, and copper chloride and/or borax. Each preservative was used in treatment of wood blocks in a reduced-pressure method to measure its treatability. The treated wood blocks were placed in hot water for 3 days to examine the stability of the preservatives against hot-water leaching. The preservatives successfully penetrated into wood blocks, probably due to the use of ammonium hydroxide as a dissociating agent. However, the stability of okara-based preservatives dropped as the concentration of acid in the solutions used for hydrolysis of okara increased. The treatability and leachability of the preservatives were not affected by hydrolysis temperature but were negatively affected by the addition of borax. Leached wood blocks treated with okara-based preservatives and exposed to decay fungi Gloeophyllum trabeum and Postia placenta over 12 weeks showed good decay resistance. Okara-based wood preservatives can protect wood against fungal attack as effectively as CuAz, and have potential for use as environmentally friendly wood preservatives.

Change in Chemical Composition of Acer mono Saps Collected in Different Region and Time Depending on Storing Period

This study was performed to investigate change in chemical composition of Acer mono saps collected in Hamyang, Inje, Namyangju and Yeongwol depending on storing period. pH of A. mono sap was in the range of 4.43~5.68, and it was decreased rapidly with the increase of storing period. A. mono sap collected in Yeongwol in Feb. 22 contained 2.06% sucrose. Degradation of sucrose was occurred when storing period was extended, and it caused production of organic acid like pyruvic acid, lactic acid, acetic acid and ethanol. Detected minerals in A. mono sap were K, Ca, Na, Mg, P, Si, Al, Mn, Fe, Cu and Zn, however, K and Ca content reached 93%. A. mono sap collected in Inje in Mar. 03 contained 131.72 mg/, which was especially high K content among the A. mono sap. 1.55~3.50 mg/ of Ascorbic acid was found in the A. mono sap. Sap collected in early date was less degraded.

Antifungal efficacy of environmentally friendly wood preservatives formulated with enzymatic‐hydrolyzed okara, copper, or boron salts

Okara, an organic waste product obtained from soy milk production, was used with copper chloride or sodium borate to formulate new wood preservatives as a substitute for expensive wood preservatives, such as copper-azole-based preservatives and ammoniacal copper quaternary. Before formulating the preservatives, okara was hydrolyzed by enzymes (cellulase, pectinase, and protease) to augment penetration and fix the biocide salts of the preservatives into wood blocks. The preservatives were injected into wood blocks by vacuum pressure to measure the treatability of the preservatives. The treated wood blocks were placed in hot water for 3 d to measure leachability. The treatability and leachability of the preservatives were affected by the type and loading amount of enzymes and the addition of sodium borate into okara-based wood preservative formulations. The treatability and leachability of the preservatives formulated with copper chloride and okara hydrolysates were 63.38 and 3.15%, and those of the preservatives with copper chloride, okara hydrolysates, and sodium borate were 61.47 and 3.32%, respectively. Despite the hot water leaching, wood blocks treated with preservatives formulated with 2% cellulase, pectinase, and protease hydrolyzed okara, CuCl(2), and sodium borate showed only 1.98% average weight loss against Fomitopsis palustris over 12 weeks. Microscopic observation revealed how okara-based preservatives work in wood blocks. Okara has potential as a raw material for cost-effective and environmentally friendly wood preservatives.

Involvement of extracellular and intracellular enzymes of Ceriporia sp. ZLY-2010 for biodegradation of polychlorinated biphenyls (PCBs)

This study examined the interrelation between the biodegradation of polychlorinated biphenyls (PCBs) by Ceriporia sp. ZLY-2010 and its fungal enzyme systems. The degradation rates of Aroclor 1254 and 1260 were 29.01% on day 5 and 36.80% on day 10, respectively. MnP (Manganese dependent peroxidase) and laccase activities showed the greatest increases in the samples containing Aroclors, indicating that extracellular enzymes of Ceriporia sp. ZLY-2010 were affected by the addition of Aroclors. However, the relationship between the biodegradation rate and extracellular enzymes might be obscured by the complexity of the biodegradation process. Cytochrome P450 monooxygenase was inhibited and the biodegradation rate of the Aroclor decreased by adding the inhibitor 1-aminobenzotriazole. Two-dimensional gel electrophoresis showed that intracellular enzymes play a significant role in the biodegradation of Aroclor. Complex extracellular and intracellular enzyme systems in Ceriporia sp. ZLY-2010 play an important role in degrading PCBs. Physiological changes of Ceriporia sp. ZLY-2010 caused by PCBs appeared to affect biodegradation of PCBs. However, it is necessary to further study the unidentified enzymes related to the biodegradation of Aroclor.

Evaluation of correlation between glucan conversion and degree of delignification depending on pretreatment strategies using Jabon Merah

The main purpose of this study was to investigate the glucan conversion rate after enzymatic hydrolysis depending on the treatment methods and conditions with changes in the chemical composition of treated solid fraction of Jabon Merah. The glucan conversion rate (17.4%) was not significantly improved after liquid hot water treatment (1st step) even though most of the hemicellulose was dissolved into liquid hydrolysate. Subsequently, dilute acid, organosolv, and peracetic acid treatment (2nd step) was conducted under various conditions to enhance glucan conversion. Among the 2nd step treatment, the glucan conversion rate of organosolv (max. 46.0%) and peracetic acid treatment (max. 65.9%) was increased remarkably through decomposition of acid-insoluble lignin (AIL). Finally, the glucan conversion rate and AIL content were highly correlated, which was revealed by the R-squared value (0.84), but inhibitory factors including cellulose crystallinity must be considered for advanced glucan conversion from highly recalcitrant biomasses, such as Jabon Merah.

Changes of Furfural and Levulinic Acid Yield from Small-diameter Quercus mongolica Depending on Dilute Acid Pretreatment Conditions

본 연구에서는 국산 소경 신갈나무를 이용하여 약산 전처리를 실시하고, 당으로부터 변환된 푸르푸랄 및 레불린산의 함량 변화를 평가하였다. 약산 전처리는 반응온도(140-180℃), 반응시간(10-30분), 황산 촉매 농도(0-2%, w/w)에 따라 수행하였고, 전처리 후 액상 내 글루코오스, XMG (자일로오스 + 만노오스 + 갈락토오스), 푸르푸랄, 레불린산의 함량을 측정/분석하였다. 글루코오스는 반응온도의 상승, 반응시간과 황산 촉매 농도의 증가에 의해 그 함량이 높아져최대 16.02%까지 나타났으나, 황산 촉매 농도 2% (반응온도 170℃ 이상, 반응시간 20분 이상)에서 함량이 감소하였다. 한편, XMG 함량은 반응온도의 영향을 크게 받았고, 반응온도와 황산 촉매 농도의 증가에 따라 1.63%까지 감소하였으며, 반응시간의 증가에 의한 함량변화는 적었다. 푸르푸랄 함량은 반응온도, 반응시간, 황산 촉매 농도 증가에 따라 높아져 초기시료 중량 대비 최대 7.61% (반응온도 180℃, 반응시간 20분, 1% 황산 촉매 농도)로 나타났으나, 전처리 조건이 최대 푸르푸랄 함량 조건보다 가혹해지면서 감소하는 경향이 발생하였다. 레불린산 함량은 반응온도, 반응시간, 황산 촉매 농도가 증가함에 따라 높아졌고, 특히 반응온도 170℃ 이상에서 급격한 함량 증가를 확인하였으며, 최대 10.98% (반응온도 180℃, 반응시간 30분, 2% 황산 촉매 농도)로 나타났다. 반면 황산 촉매를 투입하지 않았을 경우 모든 반응온도, 반응시간 조건에서 푸르푸랄 및 레불린산 함량은 1% 미만으로 나타났다.

Screening of Outstanding White Rot Fungi for Biodegradation of Organosolv Lignin by Decolorization of Remazol Brilliant Blue R and Ligninolytic Enzymes Systems

본 연구에서는 백색부후균의 리그닌 분해 효소 시스템을 이용하여, 다양한 균주 중에서 목질계 바이오매스 유기용매 전처리 과정에서 발생한 리그닌(유기용매 리그닌)의 생분해에 적합한 우수 균주를 선별하고자 하였다. 우선 분양받은 15개의 백색부후균을 대상으로 shallow stationary cultur (SSC)배지와 malt extract broth(MEB)배지에 유기용매 리그닌의 첨가에 따른 Remazol Brilliant Blue R (RBBR)의 흡광도 변화를 측정하였다. RBBR 탈색능 결과, SSC 배지에서 Ceriporiopsis subvermispora, Ceriporia lacerate, Fomitopsis insularis, Phanerochaete chrysosporium, Polyporus brumalis, Stereum hirsutum 등 6종의 백색부후균에서 급격한 흡광도 변화를 나타냈다. 배양 초기에 급격한 흡광도 변화를 나타낸 6개의 백색부후균을 대상으로 균체 외단백질 농도 및 리그닌 분해 효소 활성을 측정하였다. 선발된 6개의 균 중에서 S. hirsutum과 P. chrysosporium은 유기용매 리그닌을 첨가한 실험구에서 높은 단백질 농도가 측정되었다. 반면, 리그닌 분해 효소 활성은 F.insularis에서 배양 6일째에 manganese peroxidase (MnP) 활성이 1,545 U/mg, laccase 활성은 1,259 U/mg으로 최고 활성을 나타냈다. 결론적으로, 균체 외 단백질 농도 및 리그닌 분해 효소 활성이 전반적으로 높았던STH*와 MnP 및 laccase의 활성이 가장 높은 FOI가 유기용매 리그닌 생분해에 유리하게 작용할 것으로 판단된다.

Investigation of the Effective Catalyst for Organosolv Pretreatment of Liriodendron tulipifera

ABSTRACT Organosolv pretreatments which utilized sulfuric acid, sodium hydroxide and ammonia as catalysts were conducted to screen the effective catalyst for organosolv pretreatment of Liriodendron tulipifera. The enzy-matic hydrolysis was achieved effectively with sulfuric acid (74.2%) and sodium hydroxide (63.7%). They were thus considered as effective catalysts for organosolv pretreatment of L. tulipifera. The organosolv pre-treatments with sulfuric acid and sodium hydroxide showed a different behavior on the reaction mechanism. The pretreatment with sulfuric acid increased the biomass roughness and pore numbers. On the other hand, the pretreatment with sodium hydroxide enhanced the surface area due to the size reduction and minor defiberization which were caused by hemicellulose degradation at an initial stage and more de-fiberization by lignin degradation at a later stage. The organosolv pretreatment with sodium hydroxide was performed at several different conditions to evaluate effectiveness of sodium hydroxide as a catalyst for organosolv pretreatment. According to the results of enzymatic digestibility, the changes of chemical com-position and the morphological analysis of pretreated biomass, it was suggested that the pretreatment time impacted primarily on enzymatic hydrolysis. Increase in surface area during the pretreatment was a major cause for improvement in enzymatic digestibility when sodium hydroxide was used as a catalyst. Keywords : Liriodendron tulipifera, organosolv pretreatment, sulfuric acid catalyst, sodium hydroxide cat-alyst, enzymatic hydrolysis

Organosolv Pretreatment of Slurry Composting and Biofiltration of Liquid Fertilizer-Treated Yellow Poplar for Sugar Production

ABSTRACT The present study examines the influence of slurry composting and biofiltration liquid fertilizer (SCBLF) treatment on the biomass characteristics of yellow poplar, and the optimization of organosolv pretreatment for sugar production. After SCBLF treatment, total exchangeable cation contents of yellow poplar was increased from 3.1 g kg -1 to 4.4 g kg -1 , and as a result, biomass production of yellow poplar was also enhanced by 82.3%. Organosolv pretreatment was conducted with three independent variables: 1) reaction temperature: 133.2℃ to 166.8℃; 2) acid concentration: 0.2% to 1.8%; and 3) reaction time: 1.6 min to 18.4 min. Reaction temperature was the most significant variable in water insoluble solid (WIS) recovery rate. High overall sugar yield was attained from pretreatment conditions approximately 50% of WIS recovery rate, and the highest overall glucose yield (44.0%) was achieved from pretreatment at 140℃ with 1.5% acid concentration for 5 min. Consequently, 21.1% of glucose and 5.8% of xylose were produced from the organosolv pretreatment of SCBLF-treated 8-year-old yellow poplar.Keywords : slurry composting and biofiltration, yellow poplar, organosolv retreatment, biomass production, sugar production