Performance and Fouling in Pre-Denitrification Membrane Bioreactors Treating High-Strength Wastewater from Food Waste Disposers

The study investigated the performance of the pre-denitrification membrane bioreactor (MBR) process to treat high-strength wastewater generated from food waste disposals. Extracellular polymeric substances (EPS) as membrane foulant and microbial community profiles were analyzed under different hydraulic retention time (HRT) operation conditions. The pre-denitrification MBR was effective for treating food wastewater with high chemical oxygen demand (COD)/N resulting in high total nitrogen (TN) removal efficiency. The operational data showed that effluent qualities in terms of COD, TN, and TP improved with longer HRT. However, membrane fouling potential as shown by specific membrane fouling rate and specific resistance to filtration (SRF) increased as HRT increased. The longer HRT conditions or lower influent loading led to higher levels of bound EPS while HRT did not show large effects on the level of soluble microbial products (SMP). The restriction fragment length polymorphism (RFLP) analysis showed similar microbial banding patterns from the sludges generated under different HRT conditions, indicating that HRT had minimal effects on the composition of microbial communities in the system. All these results suggest that the MBR with pre-denitrification is a feasible option for treating high-strength food wastewater and that different HRT conditions could affect the operational performance and the fouling rate, which is governed via changes in microbial responses through EPS in the system

Targeting Mannitol Metabolism as an Alternative Antimicrobial Strategy Based on the Structure-Function Study of Mannitol-1-Phosphate Dehydrogenase in Staphylococcus aureus

Mannitol-1-phosphate dehydrogenase (M1PDH) is a key enzyme in Staphylococcus aureus mannitol metabolism, but its roles in pathophysiological settings have not been established. We performed comprehensive structure-function analysis of M1PDH from S. aureus USA300, a strain of community-associated methicillin-resistant S. aureus, to evaluate its roles in cell viability and virulence under pathophysiological conditions. On the basis of our results, we propose M1PDH as a potential antibacterial target. In vitro cell viability assessment of ΔmtlD knockout and complemented strains confirmed that M1PDH is essential to endure pH, high-salt, and oxidative stress and thus that M1PDH is required for preventing osmotic burst by regulating pressure potential imposed by mannitol. The mouse infection model also verified that M1PDH is essential for bacterial survival during infection. To further support the use of M1PDH as an antibacterial target, we identified dihydrocelastrol (DHCL) as a competitive inhibitor of S. aureus M1PDH (SaM1PDH) and confirmed that DHCL effectively reduces bacterial cell viability during host infection. To explain physiological functions of SaM1PDH at the atomic level, the crystal structure of SaM1PDH was determined at 1.7-Å resolution. Structure-based mutation analyses and DHCL molecular docking to the SaM1PDH active site followed by functional assay identified key residues in the active site and provided the action mechanism of DHCL. Collectively, we propose SaM1PDH as a target for antibiotic development based on its physiological roles with the goals of expanding the repertory of antibiotic targets to fight antimicrobial resistance and providing essential knowledge for developing potent inhibitors of SaM1PDH based on structure-function studies.IMPORTANCE Due to the shortage of effective antibiotics against drug-resistant Staphylococcus aureus, new targets are urgently required to develop next-generation antibiotics. We investigated mannitol-1-phosphate dehydrogenase of S. aureus USA300 (SaM1PDH), a key enzyme regulating intracellular mannitol levels, and explored the possibility of using SaM1PDH as a target for developing antibiotic. Since mannitol is necessary for maintaining the cellular redox and osmotic potential, the homeostatic imbalance caused by treatment with a SaM1PDH inhibitor or knockout of the gene encoding SaM1PDH results in bacterial cell death through oxidative and/or mannitol-dependent cytolysis. We elucidated the molecular mechanism of SaM1PDH and the structural basis of substrate and inhibitor recognition by enzymatic and structural analyses of SaM1PDH. Our results strongly support the concept that targeting of SaM1PDH represents an alternative strategy for developing a new class of antibiotics that cause bacterial cell death not by blocking key cellular machinery but by inducing cytolysis and reducing stress tolerance through inhibition of the mannitol pathway

Deep learning-based statistical noise reduction for multidimensional spectral data

In spectroscopic experiments, data acquisition in multi-dimensional phase space may require long acquisition time, owing to the large phase space volume to be covered. In such case, the limited time available for data acquisition can be a serious constraint for experiments in which multidimensional spectral data are acquired. Here, taking angle-resolved photoemission spectroscopy (ARPES) as an example, we demonstrate a denoising method that utilizes deep learning as an intelligent way to overcome the constraint. With readily available ARPES data and random generation of training data set, we successfully trained the denoising neural network without overfitting. The denoising neural network can remove the noise in the data while preserving its intrinsic information. We show that the denoising neural network allows us to perform similar level of second-derivative and line shape analysis on data taken with two orders of magnitude less acquisition time. The importance of our method lies in its applicability to any multidimensional spectral data that are susceptible to statistical noise.Comment: 8 pages, 8 figure

A phenomenological inquiry into the problem of meaning in architecture

Ph.D.Libero Andreott

중금속 함유 식물체부산물의 처리를 위한 혐기성소화에 대한 연구

학위논문 (박사)-- 서울대학교 대학원 : 건설환경공학부, 2016. 8. 김재영.중금속 오염토양의 식물상정화공법 이후 발생되는 식물체부산물은 식물의 생장 과정에서 토양 내 존재하는 중금속을 흡수하고 이를 체내에 축적한 상태로 수확된다. 따라서 식물상정화공법 이후 발생되는 식물체부산물은 적절한 방법을 통해 처리되어야 한다. 최근 식물체부산물의 혐기성소화를 통한 바이오가스 생산에 대한 연구가 많은 연구자들에 의해 관심을 받고 있으며, 이와 관련하여 바이오가스 생산을 위한 바이오매스의 재배를 중금속 오염토양에서 실시할 경우 식물의 생장 과정 중 중금속 흡수를 통한 토양의 정화를 실시할 수 있을 뿐만 아니라 수확된 식물체부산물은 바이오가스 생산을 위한 연료로 사용될 수 있는 장점이 있다. 중금속 오염토양에서 수확된 식물체부산물 내 포함되어 있는 중금속은 혐기성소화 공정 내에서 혐기성 미생물의 대사와 활동에 영향을 미쳐 공정 자체의 실패를 초래하는 요인이 될 수 있다. 본 연구에서는 중금속 오염토양에서 수확된 해바라기부산물을 대상으로 중금속 함유 식물체부산물의 처리에 대한 혐기성소화 적용 타당성을 검증하였다. 또한 연속식 반응조의 물질수지를 바탕으로 혐기성소화 공정 내 중금속의 거동특성을 반영하는 중금속 농도 예측 모형의 개발을 실시하였다. 서로 다른 농도의 중금속 농도로 오염된 토양으로부터 수확된 해바라기부산물을 대상으로 BMP (Biochemical methane potential) test를 실시하여 최대메탄발생량을 측정하고 이를 비교함으로써 중금속을 함유하는 식물체부산물의 혐기성소화를 통한 처리 가능성을 평가하였다. 그 결과 비오염토양에서 수확된 해바라기부산물부터 해바라기가 정상적으로 생장할 수 있는 최고 수준의 중금속 농도로 오염된 토양에서 수확된 해바라기부산물에 이르기까지 총 4종의 각기 다른 중금속 농도를 함유하는 해바라기부산물 간의 최대메탄발생량에서 유의미한 차이는 관찰되지 않았다 (201.60±11.39 - 227.38±15.59 mL CH4/g VS). 이는 실험 종료 후 확인된 혐기성 미생물의 활동에 직접적으로 영향을 줄 수 있는 액상 내 중금속의 양이 대조군과 실험군들에서 유사한 수준으로 존재하였으며, 모두 문헌에서 제시하고 있는 저해 수준 이하였기 때문으로 판단된다. 결국 해바라기가 정상적으로 생장할 수 있는 수준의 중금속 오염토양에서 수확된 해바라기부산물은 중금속에 의한 영향이 없이 혐기성소화를 통한 처리가 가능할 수 있음을 의미한다. 실험실 규모의 연속식 완전혼합반응조 (CSTR)를 중온의 혐기성 조건에서 약 1,100 일 동안 운전함으로써 중금속을 함유하는 식물체부산물의 혐기성소화에 대한 공정의 안정성을 장기간에 걸쳐 평가하였다. 실험에는 폐광산 인근의 중금속 오염토양에서 실제 식물상정화공법을 실시하고 수확된 해바라기부산물을 사용하였다. 반응조 운전 결과, 비오염토양에서 수확된 일반 식물체부산물을 대상으로 혐기성소화를 실시했던 기존의 선행연구와 유사한 유기물부하량 (OLR) 2.0 g VS/L/day 및 수리학적체류시간 (HRT) 20일의 조건까지 반응조 액상 내 중금속 농도는 혐기성 미생물의 활동에 저해를 줄 수 있다고 보고되는 농도 이하로 유지되었다. 반응조의 운전 안정성을 평가할 수 있는 지표인 바이오가스 발생량, 바이오가스 내 메탄함량, 유기물제거율, 지방산 농도, 알칼리도, 그리고 pH 등에 대한 분석을 실시하였다. 분석 결과 확인된 지표들은 모두 반응조 운전 기간에 걸쳐 큰 변화를 보이지 않고 안정적인 범위를 유지됨에 따라 반응조가 외부로부터 유입된 독성물질에 의한 영향을 받지 않고 안정적으로 운전이 이루어졌음을 알 수 있었다. 또한 반응조 운전 기간 중 반응조 내 미생물 군집을 함께 확인한 결과, 대부분 셀룰로오스계 바이오매스의 혐기성소화조에서 관찰되는 미생물들이 시간의 흐름에 따라 기질에 순응하며 유사한 군집을 형성해 나아감을 확인하였다. 반응조 운전 후반부에 이르러 반응조 운전 초기에 비해 메탄생성균 (methanogen) 중 유기산의 축적과 관련된 Methanosarcina 속 (genus)이 점차 증가하였고, 이는 지속적인 유기물부하량의 증가와 수리학적체류시간의 감소로 인한 영향이 나타날 수 있음을 의미한다. 결국 중금속을 함유하는 식물체부산물의 혐기성소화 공정은 비오염토양에서 수확된 일반 식물체부산물과 같은 조건에서 부산물 내에 포함된 중금속의 영향을 받지 않고 안정적으로 운전될 수 있다. 다만 반응조 내 유기산의 축적을 피할 수 있는 적절한 운전조건 (i.e., 유기물부하량, 수리학적체류시간)에 대한 연구가 추후 수반되어야 할 것으로 판단된다. 본 연구에 사용된 해바라기부산물에는 구리, 납, 니켈, 아연, 그리고 카드뮴이 주요 중금속으로 포함되어 있었다. 그러나 해바라기부산물의 혐기성 분해가 이뤄진 이후 혐기성 미생물의 활동에 직접적으로 영향을 미칠 수 있는 액상 내 존재하는 형태의 중금속은 오직 구리와 아연만이 관찰되었다. 해바라기부산물의 분해와 부산물의 분해로 인해 액상 내에 존재하는 중금속의 양을 살펴보면 중온 혐기성소화 조건에서 부산물은 약 50일에 걸쳐 최초 투입된 양의 60% (휘발성고형물 중량비)가 분해되었지만 구리와 아연은 최초 투입된 양의 40% (총 중량비)가 부산물로부터 빠져나와 최종적으로 액상 내에 존재하는 것으로 확인되었다. 이는 중금속의 혐기성소화조 내 거동 특성을 통하여 설명될 수 있으며, 이온 형태의 중금속은 중금속별 특성에 따라 매우 복잡한 시스템 특성을 갖는 혐기성소화조 내에서 침전 또는 흡착을 통해 액상 내에서 제거될 수 있다. 해바라기 부산물 내에 포함되어 있는 개별 중금속의 특성을 살펴보면 피어슨의 분류 (Pearsons classification)에 따라 납과 카드뮴은 황 (sulfur) 또는 수산화이온 (OH-)과 잘 결합될 수 있어 침전을 통해 액상에서 제거될 수 있으며, 실제 Visual MINTEQ를 이용한 중금속 이온의 존재형태 예측 결과에서도 대부분이 Pb(HS)2 와 Cd(HS)2 의 형태로 존재하는 것을 확인하였다. 또한 침전이 잘 이루어지지 않는 구리, 니켈, 아연 중 니켈은 흡착실험 결과 슬러지와 해바라기부산물 모두에 높은 결합 정도 (binding affinity)를 갖는 것이 확인되었다. 결국 식물체부산물 내에 포함된 모든 중금속은 혐기성소화에 영향을 미칠 수 있는 잠재적인 영향인자이나, 부산물의 분해에 따라 부산물로부터 빠져 나온 이후 이온상태로 존재할 때의 거동 특성에 따라 일부 중금속만이 최종적으로 혐기성 미생물의 활동에 영향 줄 수 있을 것으로 판단된다. 마지막으로 이러한 중금속의 거동 특성을 반영하며 연속식반응조의 물질수지를 바탕으로 하는 혐기성소화조 내 중금속 농도 예측 모형의 개발을 실시하였다. 개발된 모형 내 변수들에 대한 민감도 분석과 모형을 통한 계산이 정상적으로 이루어지는지 여부를 확인하기 위한 검증 (verification) 과정을 수행하였다. 최종적으로는 개발된 예측 모형을 이용한 계산값과 앞선 장의 연속식반응조 운전 결과 중 실측된 중금속 농도의 비교를 통한 모형의 유효성확인 (validation)을 실시하였다. 계산값과 실측값의 비교 결과 모형은 ±20% 오차범위 수준에서 혐기성소화조 내 중금속 농도 변화 경향을 비교적 잘 예측하는 것으로 나타났다. 개발된 모형을 이용하여 기질의 분해속도상수 (k)와 부산물 내 중금속 농도에 따른 반응조 내 중금속 농도를 표현하는 중금속 함유 식물체부산물의 혐기성소화조 설계 가이드를 제공할 수 있을 것으로 사료된다. 다만 본 연구에서 개발된 모형은 계산의 편리성을 위한 불확실성을 내재하는 가정들을 일부 포함하고 있기 때문에 이러한 가정의 검증과 개선을 통해 모형의 예측 결과에 대한 정확성을 제고할 필요가 있을 것으로 판단된다.Due to endogenous contaminants, treatment methods of crop residues from contaminated sites must be carefully selected considering contaminant separation, environmental impact, and economical concerns. Contaminated residues are generally disposed of by composting, pyrolysis, direct disposal, incineration, ashing, and anaerobic digestion. Anaerobic digestion is a biological process in which microorganisms degrade organic matter and convert into biogas as the end product. Agricultural crop residues are an important source of biomass that can be utilized as a substrate in anaerobic digestion. Anaerobic digestion for crop residues has been applied as an effective technology in terms of renewable energy production, byproduct utilization, and agricultural waste reduction. For these reasons, anaerobic digestion could be the appropriate option for crop residues from heavy metal contaminated sites with considerations in terms of the aforementioned categories (i.e., contaminant separation, environmental impact, and economical concerns) among various treatment methods. However, heavy metals have been known to adversely affect the anaerobic digestion process, and the fate and effect of heavy metals in crop residues during anaerobic digestion needs to be addressed. Firstly, biochemical methane potential (BMP) tests using sunflowers (i.e., Helianthus annuus) harvested from four differential levels of heavy metals containing soils were conducted to investigate the applicability of anaerobic digestion for heavy metal containing crop residues. According to the results, the methane gas production of crop residues from heavy metals containing soils were comparable to that of the control test, which was not contaminated with heavy metals. Significant adverse effects of heavy metals in crop residues on methane gas production were not observed under the experimental conditions of this study. Even though anaerobic bacterial activities are known to be typically affected by the amounts of heavy metals in the form of liquid phase, all of the observed amounts of heavy metals in this study were not only similar between the test conditions but also below the reported inhibitory levels. These findings revealed that anaerobic digestion can be an alternative to the treatment method of heavy metal-containing crop residues from phytoremediation sites. In order to investigate the long-term stability on the performance of the anaerobic digestion process, a laboratory-scale continuous stirred-tank reactor (CSTR) was operated for 1,100 days with sunflower harvested in a heavy metal contaminated site. Changes of microbial communities during digestion were identified using pyrosequencing. According to the results, soluble heavy metal concentrations were lower than the reported inhibitory level and the reactor performance remained stable up to OLR of 2.0 g VS/L/day at HRT of 20 days. Microbial communities commonly found in anaerobic digestion for cellulosic biomass were observed and stably established with respect to the substrate. Thus, the balance of microbial metabolism was maintained appropriately and stability on the performance of the anaerobic digestion was confirmed by long-term operation of laboratory-scale CSTR operation. Although the applicability and stability of anaerobic digestion for heavy metal containing crop residues were ascertained with the conducted tests, inconsistency between biodegradation ratio of biomass and releasing characteristics of heavy metals through biodegradation of biomass was observed. For better understanding of anaerobic digestion of crop residues from heavy metal phytoremediation sites without the adverse effects of heavy metals, the releasing characteristics of endogenous heavy metals should be considered for stable anaerobic digestion process. This study was conducted to examine the releasing characteristics of heavy metals from biomass and the fate of heavy metals after release. According to the volatile solids and carbon balance analyses of anaerobic batch test results, maximum of 60% by wt. of biomass was degraded. During the biodegradation, among Cd, Cu, Ni, Pb, and Zn, only Cu and Zn were observed in soluble form (approximately 40% by wt. of input mass). The results concluded the irrelevancy between degradation ratio of biomass and ratio of released heavy metals amounts from biomass. It was shown that this discordance was caused by the fate (i.e., precipitation and adsorption) of heavy metal species in solutions after being released from biomass. Thus, ultimate heavy metal concentrations in solutions, which can exert adverse effects on anaerobic digestion performance, were strongly dependent upon not only released heavy metal amounts but also their fate in solution after release. A model of the anaerobic digestion process which attempts to explain the complex patterns of the anaerobic digestion process is required to better understanding and design anaerobic digestion process. Mathematical models have provided an understanding of important inhibition patterns and have given guidelines for operation and optimization of anaerobic digesters. However, a mathematical model for prediction in change of heavy metal concentrations in anaerobic digestion process according to the degradation of heavy metal containing biomass has not been studied in previous research. For this reason, developing a mathematical model is needed for better understanding of anaerobic digestion of crop residues from heavy metal phytoremediation sites without the adverse effects of heavy metals. In this study, to simulate the change of soluble heavy metals in anaerobic digestion system, a mathematical model based on mass balance is developed. The model can describe the soluble heavy metal concentrations in anaerobic digester according to degradation of heavy metal containing crop residues. From the sensitivity analysis for the variables used in the model, OLR has the highest sensitivity with gradient of trend line. Although substrate degradation kinetic (k) has relatively low sensitivity to the change of heavy metal concentrations in liquid phase, the k value can be an important input parameter due to its variation with type of substrate. The developed model will provide useful information on anaerobic digestion process design for heavy metal containing substrate and will expand the substrate types using simple batch test for substrate degradation kinetics. Several application examples and required improvements were also discussed. However, the model developed in this study includes several uncertain assumptions for the convenience of calculation (i.e., MLSS is constant during digestion, heavy metal adsorption occurs only to MLSS, etc.). Consequently, upgrading the developed model should be accompanied by verification and improvement of the uncertain assumptions for degree of completion.CHAPTER 1. INTRODUCTION 1 1.1 Background 1 1.2 Objectives 3 1.3 Dissertation structure 3 References 5 CHAPTER 2. LITERATURE REVIEW 7 2.1 Treatment methods of heavy metal-containing crop residues 7 2.2 Anaerobic digestion of cellulosic biomass 17 2.2.1 Principle of anaerobic digestion of biomass 18 2.2.2 Structure and composition of cellulosic biomass 21 2.2.3 Anaerobic digestion of crop residues: methane production potential 25 2.3 Effects of heavy metals on anaerobic digestion 29 2.3.1 Factors of heavy metal inhibition 31 2.3.2 Chemical forms of heavy metal 32 2.3.3 Concentrations of heavy metal 33 References 35 CHAPTER 3. ANAEROBIC DIGESTION AS AN ALTERNATIVE TREATMENT METHOD FOR CROP RESIDUES FROM HEAVY METAL CONTAMINATED SITES 43 3.1 Introduction 43 3.2 Materials and methods 47 3.2.1 Preparation and characterization of substrate 47 3.2.2 General methods of BMP test 51 3.3 Results and discussion 54 3.3.1 Characterization of substrate 54 3.3.2 Effect of heavy metal concentrations in crop residues on anaerobic digestion 58 3.4 Summary 68 References 69 CHAPTER 4. STABILITY OF ANAEROBIC DIGESTION FOR CROP RESIDUES FROM HEAVY METAL CONTAMINATED SITES WITH LAB-SCALE CSTR 74 4.1 Introduction 74 4.2 Materials and methods 77 4.2.1 Substrate and inoculum 77 4.2.2 CSTR operation 80 4.2.3 Analytical methods 82 4.2.4 Microbial community analysis: DNA extraction, PCR, and pyrosequencing 83 4.3 Results and discussion 86 4.3.1 Heavy metal concentrations in liquid fraction of CSTR 86 4.3.2 Digestion performance 89 4.3.3 Microbial community analysis 94 4.4 Summary 109 References 110 CHAPTER 5. RELEASING CHARACTERISTICS OF HEAVY METALS FROM CROP RESIDUES UNDER ANAEROBIC CONDITION 116 5.1 Introduction 116 5.2 Materials and methods 119 5.2.1 Characterization of heavy metal-containing biomass 119 5.2.2 Biomass degradation and heavy metal releasing during anaerobic digestion 122 5.2.3 Prediction of heavy metal existing form after releasing by Visual MINTEQ 3.0 125 5.2.4 Biosorption test under anaerobic condition 126 5.3 Results and discussion 128 5.3.1 Biodegradation of biomass under anaerobic condition 128 5.3.2 Heavy metals releasing from biomass according to biodegradation 131 5.3.3 Major existing form of released heavy metals in solution (predicted by Visual Minteq 3.0) 134 5.3.4 Biosorption of heavy metals onto sorbents (differential binding affinity) 138 5.4 Summary 143 References 144 CHAPTER 6. A MODEL DEVELOPMENT FOR PREDICTION OF HEAVY METAL CONCENTRATIONS WITH DEGRADATION OF CROP RESIDUES 148 6.1 Introduction 148 6.2 Model development 150 6.3 Sensitivity analysis 158 6.4 Model verification and validation 162 6.4.1 Model verification 162 6.5 Application of developed model 169 6.5.1 Maximum OLR for stable operation without inhibition of heavy metal 170 6.5.2 Distribution of heavy metals between solid/liquid phase 172 6.5.3 Change of soluble heavy metal concentrations by substrate characteristics 174 6.6 Summary 176 References 177 CHAPTER 7. CONCLUSIONS 179 국문 초록 182Docto

Optimization of an Empirical Model for Microorganism-Immobilized Media to Predict Nitrogen Removal Efficiency

The purpose of this study was to develop a model to predict the total nitrogen (T-N) concentration in treated wastewater effluent when microorganism-immobilized media are applied. The operational data for this study were obtained using synthetic wastewater and actual wastewater within a lab-scale reactor. The organic matter removal, nitrification, and denitrification rates were 81.8, 87, and 82.9%, respectively. These rates adequately satisfied the effluent water quality standard. The observed parameters from the lab-scale reactor operation were applied to develop the optimization model, and the model showed correlation coefficients as 0.9785 and 0.9811 for nitrification and denitrification efficiencies, respectively. The model predicted that T-N concentration could be reduced to <10 mg/L with the injection of the external carbon source. The predicted value for the T-N concentration was higher than the observed value from the lab-scale reactor, which operated under the same conditions. The model showed comparable values to the observed data, and the model seems to be useful for predicting related parameters in effluent water quality, with further development of the specifications required in the treatment facilities under various operating conditions

Analysis of Vertical Stiffness Characteristics Based on Spoke Shape of Non-Pneumatic Tire

Recently, research regarding non-pneumatic tires that are resistant to punctures has been actively conducted, and the spoke structure design of non-pneumatic tires has been found to be a crucial factor. This study aimed to analyze the vertical stiffness characteristics of a non-pneumatic tire based on the shape of the spoke under the application of a vertical load. The three-dimensional model of a commercial non-pneumatic tire was obtained from the manufacturer (Kumho Tire Co., Inc., Gwangju, Korea), and the vertical stiffness characteristics of the three tire models with modified spoke shapes were compared and analyzed based on a reference tire model. Results show that the vertical stiffness of the fillet applied model is most appropriate. Furthermore, the vertical stiffness characteristics of the analyzed tire models indicate that if fillets with a minimum size are applied to the spokes, the stability of the non-pneumatic tire is expected to improve

The Assessment of the Skin-Whitening and Anti-Wrinkling Effects of <i>Anemarrhena asphodeloides</i> Bunge Root Extracts and the Identification of Nyasol in a Developed Cream Product

Anemarrhena asphodeloides Bunge (A. asphodeloides Bunge) root extract contains nyasol as its main ingredient. Nyasol was extracted and prepared as a cosmetic raw material in 95% ethanol. To identify nyasol as a marker compound qualitative analysis was performed using ultra-performance liquid chromatographyi coupled with electrospray ionization–tandem mass spectrometry. Below a nyasol content of 12 μg/mL, the root extract exhibited negligible cytotoxicity. In this concentration range, melanin production in B16F10 mouse melanoma cells decreased as the concentration of nyasol increased, indicating a skin-whitening effect. In addition, an antiwrinkling effect was confirmed by evaluating the inhibition of MMP-1 protein expression in TNF-α-treated HaCaT cells by either A. asphodeloides Bunge root extract (>0.31 μg/mL) or nyasol (>0.25 μg/mL). High-performance liquid chromatography-coupled with a photodiode detector array was used to show that our extract contained 5.06 ± 0.01% nyasol. Furthermore, when this analysis method was applied for the quality control of a cream product containing 2 wt.% of A. asphodeloides Bunge root extract, the measured content of nyasol (0.1%) was over 90% of the nominal quantity. Therefore, the product was deemed to be within the required quality standards