• Journal of the Korean Wood Science and Technology
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• 제38권6호
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• pp.561-567
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• 2010

본 연구는 diethyl oxalate 처리로부터 얻어진 가문비나무 가수분해산물을 이용하여 에탄올 생산에 적합한 조건을 탐색하였다. 가문비나무 가수분해산물의 단당류 분석 결과 아라비노오스를 제외한 발효가능한 당 농도 는 29.04 g/${\ell}$이었으며 가수분해산물에 포함된 올리고머로부터 분해된 단당은 대부분 만노오스(39.26 g/${\ell}$)와 갈락토오스(12.83 g/${\ell}$)가 차지하였다. 발효저해물질인 5-HMF, furfural의 농도는 각각 0.09 g/${\ell}$, 0.04 g/${\ell}$, acetic acid는 1.4 g/${\ell}$, total phenolic compounds는 2.83 g/${\ell}$로 나타났다. 가수분해산물을 이용한 에탄올 생산 최적 pH는 6.0으로 발효 48시간 후 11.7 g/${\ell}$의 에탄올을 생산하였다. 시간당 에탄올 생산량은 pH 5.0와 5.5에서 0.15 (g/(${\ell}^*h$))로 나타났으며 pH 6.0에서는 0.24 (g/(${\ell}^*h$))로 나타났다. 시간당 생성된 에탄올 생산량은 에탄올 발효 초기 pH에 따라 차이를 나타냈다. 가수분해산물에 xylanase 20 IU를 첨가하여 올리고머를 분해한 후 발효를 실시한 결과 48시간 후 14.3 g/${\ell}$의 에탄올을 생산하였다. 이것은 xylanase를 첨가하지 않았을 때 보다 에탄올 생산량이 22.2% 증가되었음을 나타내고 있다.

• Journal of Microbiology and Biotechnology
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• 제25권6호
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• pp.893-902
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• 2015

Various Lactobacillus reuteri strains were screened for the ability to convert glycerol to 1,3-propanediol (1,3-PDO) in a glycerol-glucose co-fermentation. Only L. reuteri DSM 20016, a well-known probiotic, was able to efficiently carry out this bioconversion. Several process strategies were employed to improve this process. Co²⁺ addition to the fermentation medium, led to a high product titer (46 g/l) of 1,3-PDO and to improved biomass synthesis. L. reuteri DSM 20016 produced also ca. 3 µg/g of cell dry weight of vitamin B₁₂, conferring an economic value to the biomass produced in the process. Incidentally, we found that L. reuteri displays the highest resistance to Co²⁺ ions ever reported for a microorganism. Two waste materials (crude glycerol from biodiesel industry and spruce hydrolysate from paper industry) alone or in combination were used as feedstocks for the production of 1,3-PDO by L. reuteri DSM 20016. Crude glycerol was efficiently converted into 1,3-PDO although with a lower titer than pure glycerol (33.3 vs. 40.7 g/l). Compared with the fermentation carried out with pure substrates, the 1,3-PDO produced was significantly lower (40.7 vs. 24.2 g/l) using cellulosic hydrolysate and crude glycerol, but strong increases of the maximal biomass produced (2.9 vs 4.3 g/l CDW) and of the glucose consumption rate were found. The results of this study lay the foundation for further investigations to exploit the biotechnological potential of L. reuteri DSM 20016 to produce 1,3-PDO and vitamin B₁₂ using industry byproducts.