• Journal of Ginseng Research
• /
• 제31권4호
• /
• pp.191-195
• /
• 2007

Red ginseng sikhye is one of Korean unique beverages with the addition of effective ingredients of ginseng. Considering economical and mechanical efficiency and quality of sikhye, the optimum conditions for saccharification is to saccharify at 90 degree celsius for 3 hours in the composition of 4% of malt, 20% of steamed rice, and 6% of red ginseng power. The red ginseng sikhye has high soluble solid content over 33% compared with conventional commercial sikhye. On the other hand, ginseng sikhye, which shows low pH, has more or less higher acidity than conventional commercial one. Especially the turbidity of the red ginseng sikhye is much higher than that of commercial sikhye, due to as high amount of rice as 20% compared with 3% in the commercial one. The use of high quantity of rice affected the level of turbidity in red ginseng sikhye. In this study, we wanted to establish optimum conditions for saccharification in manufacturing red ginseng sikhye which contains effective herbal medicinal ingredients maintaining the original taste of traditional sikhye.

• Journal of the Korean Wood Science and Technology
• /
• 제36권5호
• /
• pp.56-65
• /
• 2008

In this paper experimental results are presented for the rheological behavior of high-solids saccharification of mixed northeast hardwood as a model feedstock. The experimental determination of the viscosity, shear stress, and shear rate relationships of the 10 to 20 percent slurry concentrations with constant enzyme concentrations were performed under variable rotational speed of a viscometer (2.0 to 200 RPM) at combined temperatures (50 to $30^{\circ}C$) for the initial four hours. The viscosities of saccharification slurries observed were in the ranges of 0.024 to 0.028, 0.401 to 0.058, and 0.840 to 0.087 Pa s for shear rates up to 100 reciprocal seconds at 10, 15, and 20 percent initial solids (w/v) respectively. The fluid behavior of the suspensions was modeled using the power-law, the Herschel-Bulkley, the Casson, and the Bingham model. The results showed that broth slurries were pseudoplastic with a yield stress. The model slope increased and the model intercept decreased with increasing fermentation time at shear rates normal for the fermentor. The broth slurries exhibited Newtonian behavior at high and low shear rates during initial saccharification process. The solid particle size ranged from 57.8 to $70.0{\mu}m$ for $40^{\circ}C$ and from 44.0 to 57.5 11m for combined temperatures at 10, 15, and 20 percent initial solids (w/v) respectively.

• Journal of Microbiology and Biotechnology
• /
• 제18권7호
• /
• pp.1257-1265
• /
• 2008

To lower the cost of ethanol distillation of fermentation broths, a high initial glucose concentration is desired. However, an increase in the substrate concentration typically reduces the ethanol yield because of insufficient mass and heat transfer. In addition, different operating temperatures are required to optimize the enzymatic hydrolysis (50$^{\circ}C$) and fermentation (30$^{\circ}C$). Thus, to overcome these incompatible temperatures, saccharification followed by fermentation (SFF) was employed with relatively high solid concentrations (10% to 20%) using a portion loading method. In this study, glucose and ethanol were produced from Solka Floc, which was first digested by enzymes at 50$^{\circ}C$ for 48 h, followed by fermentation. In this process, commercial enzymes were used in combination with a recombinant strain of Zymomonas mobilis (39679:pZB4L). The effects of the substrate concentration (10% to 20%, w/v) and reactor configuration were also investigated. In the first step, the enzyme reaction was achieved using 20 FPU/g cellulose at 50$^{\circ}C$ for 96 h. The fermentation was then performed at 30$^{\circ}C$ for 96 h. The enzymatic digestibility was 50.7%, 38.4%, and 29.4% after 96 h with a baffled Rushton impeller and initial solid concentration of 10%, 15%, and 20% (w/v), respectively, which was significantly higher than that obtained with a baffled marine impeller. The highest ethanol yield of 83.6%, 73.4%, and 21.8%, based on the theoretical amount of glucose, was obtained with a substrate concentration of 10%, 15%, and 20%, respectively, which also corresponded to 80.5%, 68.6%, and 19.1%, based on the theoretical amount of the cell biomass and soluble glucose present after 48 h of SFF.

• Journal of Microbiology and Biotechnology
• /
• 제24권10호
• /
• pp.1427-1437
• /
• 2014

Enzymatic hydrolysis of lignocellulosic biomass into fermentable sugars is a key step in the conversion of agricultural by-products to biofuels and value-added chemicals. Utilization of a robust microorganism for on-site production of biomass-degrading enzymes has gained increasing interest as an economical approach for supplying enzymes to biorefinery processes. In this study, production of multi-polysaccharide-degrading enzymes from Aspergillus aculeatus BCC199 by solid-state fermentation was improved through the statistical design approach. Among the operational parameters, yeast extract and soybean meal as well as the nonionic surfactant Tween 20 and initial pH were found as key parameters for maximizing production of cellulolytic and hemicellulolytic enzymes. Under the optimized condition, the production of FPase, endoglucanase, ${\beta}$-glucosidase, xylanase, and ${\beta}$-xylosidase was achieved at 23, 663, 88, 1,633, and 90 units/g of dry substrate, respectively. The multi-enzyme extract was highly efficient in the saccharification of alkaline-pretreated rice straw, corn cob, and corn stover. In comparison with commercial cellulase preparations, the BCC199 enzyme mixture was able to produce remarkable yields of glucose and xylose, as it contained higher relative activities of ${\beta}$-glucosidase and core hemicellulases (xylanase and ${\beta}$-xylosidase). These results suggested that the crude enzyme extract from A. aculeatus BCC199 possesses balanced cellulolytic and xylanolytic activities required for the efficient saccharification of lignocellulosic biomass feedstocks, and supplementation of external ${\beta}$-glucosidase or xylanase was dispensable. The work thus demonstrates the high potential of A. aculeatus BCC199 as a promising producer of lignocellulose-degrading enzymes for the biomass conversion industry.

• Journal of Microbiology and Biotechnology
• /
• 제27권1호
• /
• pp.1-8
• /
• 2017

The production of high-value chemicals from natural resources as an alternative for petroleum-based products is currently expanding in parallel with biorefinery. The use of lignocellulosic biomass as raw material is promising to achieve economic and environmental sustainability. Filamentous fungi, particularly Aspergillus species, are already used industrially to produce organic acid as well as many enzymes. The production of lignocellulose-degrading enzymes opens the possibility for direct fungal fermentation towards organic acids such as itaconic acid (IA) and fumaric acid (FA). These acids have wide-range applications and potentially addressable markets as platform chemicals. However, current technologies for the production of these compounds are mostly based on submerged fermentation. This work showed the capacity of two Aspergillus species (A. terreus and A. oryzae) to yield both acids by solid-state fermentation and simultaneous saccharification and fermentation. FA was optimally produced at by A. oryzae in simultaneous saccharification and fermentation (0.54 mg/g wheat bran). The yield of 0.11 mg IA/g biomass by A. oryzae is the highest reported in the literature for simultaneous solid-state fermentation without sugar supplements.

• Korean Chemical Engineering Research
• /
• 제47권1호
• /
• pp.89-95
• /
• 2009

볏짚은 섬유소와 헤미셀루로우스의 함유량이 높아, 바이오에탄올 생산을 위한 잠재적 가치가 매우 높은 목질계 바이오매스 원료이다. 본 연구에서는 볏짚으로부터 바이오 에탄올 생산하기 위한 전처리 공정으로써 암모니아 재순환 침출 공정을 적용하였다. 특히 생성된 고형물의 조성과 효소 가수분해도에 전처리 공정의 온도와 반응시간 그리고 암모니아의 농도가 미치는 영향을 조사하였다. 실험을 행한 전처리 공정의 온도, 반응시간, 그리고 암모니아의 범위는 차례로 $150{\sim}190^{\circ}C$, 10~90 min 그리고 0~20 wt%이다. 전처리 공정을 통하여 약 84%의 리그닌과 20~80%의 헤미셀루로우스가 용해되었다. 또, 15 wt%의 암모니아 수용액을 이용하여 $170^{\circ}C$에서 90 min 동안 전처리한 고형 잔재물의 경우 15 FPU/g of glucan의 셀루라제 효소를 첨가하여 약 90%의 효소 가수분해도를 얻을 수 있었다. 셀루라제와 자일란나아제를 함께 사용하면 가수분해도가 현저하게 향상되였으며, 이는 헤미셀루로우스가 가수분해 과정에서 중요한 방해제 역할을 하고 있음을 보여주는 것이다. $150^{\circ}C$에서 20 min 동안 15%의 암모니아수로 전처리된 시료를 이용한 동시당화발효 실험과 동시당화공동발효 실험에서는 각각 13.8 g/L(초기 glucan을 기준으로 81%)와 15.2 g/L(초기 glucan과 xylan의 합을 기준으로 89%)의 에탄올이 생성되었다.

• Journal of Microbiology and Biotechnology
• /
• 제20권4호
• /
• pp.718-726
• /
• 2010

A selected fungal strain, for production of the raw-starchdigesting enzyme by solid-state fermentation, was improved by two repeated sequential exposures to ${\gamma}$-irradiation of $Co^{60}$, ultraviolet, and four repeated treatments with Nmethyl-N'-nitrosoguanidine. The mutant strain Aspergillus sp. XN15 was chosen after a rigorous screening process, with its production of the raw-starch-digesting enzyme being twice that of usual wild varieties cultured under preoptimized conditions and in an unsupplemented medium. After 17 successive subculturings, the enzyme production of the mutant was stable. Optimal conditions for the production of the enzyme by solid-state fermentation, using wheat bran as the substrate, were accomplished for the mutant Aspergillus sp. XN15. With the optimal fermentation conditions, and a solid medium supplemented with nitrogen sources of 1% urea and 1% $NH_4NO_3$, 2.5 mM $CoSO_4$, 0.05% (v/w) Tween 80, and 1% glucose, the mutant Aspergillus sp. XN15 produced the raw-starch-digesting enzyme in quantities 19.4 times greater than a typical wild variety. Finally, XN15, through simultaneous saccharification and fermentation of a raw rice corn starch slurry, produced a high level of ethanol with $Y_{p/s}$ of 0.47 g/g.

• 한국조리학회지
• /
• 제21권1호
• /
• pp.30-41
• /
• 2015

보리의 이용증대와 식혜 제조 시 개선되어야 할 문제점인 엿기름 함량의 부족을 해결하기 위하여 보리의 종류(자수정보리, 검정보리, 늘보리, 늘찰보리, 쌀보리, 쌀찰보리)를 달리하여 전통음료인 식혜를 제조한 후 품질특성을 조사한 결과는 다음과 같다. 보리 입자의 장폭비를 측정한 결과, 검정보리가 가장 높았으며, 자수정보리가 가장 작았다. 보리밥알의 수분은 54.96~71.74%의 함량을 보였다. 당화액의 pH는 5.40~5.63의 범위였으며, 가용성 고형분 함량은 15.37~18.73 brix%의 범위로, 늘찰보리로 제조한 식혜의 당화액의 가용성 고형분 함량이 가장 높으며, 검정보리로 제조한 식혜에서 가장 낮았다. 환원당 측정결과, 4.35~7.42 mg/ 100 g의 값을 보였으며, 늘찰보리에서 가장 높은 환원당의 값을 검정보리에서 가장 낮은 환원당 값을 보여, 가용성 고형분함량과 유사한 결과를 보였다. 밥알과 당화액의 명도, 적색도, 황색도 모두 검정보리에서 낮게 나타났다. 보리식혜의 특성차이 검사 결과, 밥알의 통통함은 검정보리가 강하게 평가되었으며, 늘찰보리가 낮게 평가되었다. 밥알의 삼킨 후의 느낌은 검정보리가 강하게, 늘찰보리가 낮게 평가되었으며, 밥알의 통통함 항목과 상관관계를 보였다. 기호도 검사 결과, 외관은 쌀찰보리와 쌀보리로 만든 식혜가 높았으며, 냄새는 자수정보리가 가장 좋게 평가되었다. 텍스처에서는 쌀보리와 쌀찰보리가 높은 기호도를 보였다. 전체적인 기호도에서 쌀보리로 제조한 식혜가 높은 기호도를 보였다. 위와 같이 보리의 품종에 따라 식혜 품질의 차이를 보였다. 특히, 늘찰보리와 쌀보리로 식혜 제조 시 엿기름의 함량을 늘리지 않으면서도 당도를 높이는 데 도움을 줄 수 있을 것으로 판단된다.

• 신재생에너지
• /
• 제3권1호
• /
• pp.38-45
• /
• 2007

To characterize thermo-chemical feature of sugar conversion of woody biomass, poplar wood ($Populus\;alba{\times}glandulosa$) powder was treated with supercritical water system. Supercritical water treatment (SCWT) was performed for 60 seconds at different temperatures (subcritical zone 350; supercritical zone $300,\;400,\;425^{\circ}C$) under two pressures $230{\pm}10atm$ as well as $330{\pm}10atm$, respectively, using flow type system. After separation of solid residues from SCWT products, the monomeric sugars in aqueous part converted from poplar wood powder were quantitatively determined by high performance anionic exchange chromatography [HPAEC] equipped with PAD detector and Carbo Pac PA10 column. As the temperature treated increased, the degradation of poplar wood powder was enhanced and ca 83% of woody biomass was dissolved into the water at $425^{\circ}C$. However, the pressure didn't help the degradation of biomass components. At subcritical temperature range, xylose was first formed by degradation of xylan, which is main hemicellulose component in hardwood species, while cellulose degradation started at the transition zone between sub and supercritical conditions and was remarkably accelerated at the supercritical temperature. In the supercritical water system the maximum yield of monomeric sugars amounts to ca. 7.3% based on oven dried wood weight at $425^{\circ}C$.

• 한국미생물·생명공학회지
• /
• 제31권3호
• /
• pp.257-263
• /
• 2003

고체상태배양에서 섬유소분해효소의 고 생산을 위해 기질로서 다양한 섬유순폐기물을 검토한 결과, 주정박과 볏짚을 1:1의 혼합기질로 사용하였을 때 13.98 FPA를 얻었다. 효소생산을 높이기 위해 주정박과 볏짚의 혼합기질에 질소원으로서 콩비지를 1:1:1로 혼합하였을 때 15.22 FPA의 효소활성을 얻을 수 있었다. 이때의 최적의 함수율, pH, 온도는 각각 70%, 5.0, 3$0^{\circ}C$이었다. 최적배양조건에서 배양 5일째 FPA, CMCase, Xylanase, $\beta$-glucosidase 및 Avicelase의 효소활성은 각각 15.22, 69.1, 83.9, 29.2 및 4.2 unit/g-SDW이었다. T. harzianum FJI의 섬유소폐기물을 이용한 고체상 태배양의 경제적인 효소생산은 섬유소폐기물의 생물학적 당화기술에 크게 기여할 것이다.