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Saccharification versus simultaneous saccharification and fermentation of kraft pulp

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International Journal of Agricultural and Biological Engineering 2012年第1期5卷 48-55页

作者： Nichole A.Bauer william r.gibbons Biology-Microbiology Department South Dakota State UniversityBrookingsSD 57007USA

Enzymes are a significant cost in cellulosic ethanol production,minimizing their use would be desirable as long as ethanol yields and productivities are not *** aim was to evaluate the effects of enzyme dosage on conversion of cellulose to *** pulp,an intermediate in paper production,was used to represent a fractionated cellulose *** were conducted in a 5 L BioFlow bioreactor(2-3 L working volume)with agitation rate varied(80-900 r/m)to provide acceptable *** on survey of the literature,an average dosage for cellulase(34 FPU/g glucan)andβ-glucosidase(135 CBU/g glucan)was calculated,and these were set as the 100%*** of 1%,7%,13%,33%,67%,100%,133%were tested,using Novozyme Celluclast 1.5 L(cellulase)and Novozyme 188(β-glucosidase)in a 4.8%(dry mass)kraft pulp *** recommended dosages are at the low end of this spectrum,at 12 g/g glucan for Celluclast 1.5 L(35%dosage)and 1.2 g/g glucan for Novozyme 188(0.9%dosage).Saccharification trials(50oC)showed a typical dosage response,with the 133%dosage achieving the highest sugar concentration(~59 g/L glucose)and saccharification rate(2.45 g/L/h),with a specific rate of 2.2×10-4 g glucose/unit enzyme/*** the 13%enzyme dosage resulted in the highest specific saccharification rate(2.9×10-4 g glucose/unit enzyme/h).Simultaneous saccharification and fermentation(SSF)trials(35oC)were conducted using Saccharomyces cerevisiae or Candida molischiana to compare enzyme dosages of 33%,67%,100%,and 133%.Ethanol titers and productivities were similar for trials with 67%or more of the literature average enzyme dosage,however were lower at the 33%enzyme *** enzyme dosage can be substantially reduced from levels typically cited in the literature,but cannot be reduced to levels recommended by the manufacturer,without reduction in ethanol yield and productivity.

关键词： cellulosic ethanol fermentation saccharification renewable energy

Optimizing a nitrogen-supplemented, condensed corn soluble medium for growth of the Polyhydroxyalkanoate producer Pseudomonas putida KT217

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International Journal of Agricultural and Biological Engineering 2012年第4期5卷 62-67页

作者： Jeremy Javers william gibbons Chinnadurai Karunanithy ICM Inc.ColwichKansasKSUSA Biology and Microbiology Department South Dakota State UniversityBrookings SD57007 USA Food Engineering Food and NutritionUniversity of Wisconsin-StoutMenomonie WI 54751 USA

Pseudomonas putida KT217 produces medium-chain-length polyhydroxyalkanoate(mcl-PHA)that is of commercial interest as a biodegradable *** reduce PHA production costs,a less expensive medium to grow *** KT217 to a high cell dry weight(CDW)was *** KT217 was grown in aerated shake flasks on a condensed corn solubles(CCS)based medium that provided several organic acids and carbohydrates that were utilized for *** medium was prepared by adding various amounts of fresh CCS(100-600 g/L,or 34.9-209.4 g/L dry basis)to water and then centrifuging and *** CCS permeate media contained dry matter levels of 28.8-164.9 g/*** CCS permeate medium containing 108.4 g/L solids produced approximately 6 g CDW/L,at a growth rate of 1.03 per hour,and maximum cell population of 4×109 CFU/*** CCS is low in nitrogen,ammonium hydroxide was added at a level of 1.73 g/L,and this significantly increased the CDW(>20 g/L)produced in an aerated ***,a nitrogen supplemented CCS medium could provide a cheap source of nutrients for production of *** KT217 and PHA.

关键词： cell density cell dry weight(CDW) biodegradable plastic biocreator pH nitrogen supplement growth rate

Separation of scleroglucan and cell biomass from Sclerotium glucanicum grown in an inexpensive, by-product based medium

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International Journal of Agricultural and Biological Engineering 2011年第1期4卷 52-60页

作者： Arlene Fosmer william gibbons Biology&Microbiology Department South Dakota State UniversityBrookingsSouth Dakota 57007 USA

Scleroglucan is an extracellular polysaccharide produced by the fungi *** is stable over a broad range of temperatures,pH and salt concentration,thus having great potential in many diverse *** media for scleroglucan production contain expensive components,such as yeast extract,that make the medium cost-ineffective for some industrial *** we developed a medium which uses Condensed Corn Solubles(CCS),a nutrient-rich byproduct of corn-based ethanol production,to replace expensive *** typically used to recover scleroglucan are also expensive,and can limit *** evaluate alternative processes for scleroglucan recovery,we prepared scleroglucan in a modified version of Wang’s medium and a CCS-glucose *** samples were initially subjected to the standard recovery method to develop a complete mass balance,and then we evaluated various treatments to improve scleroglucan *** included heat treatments to lyse cells,using different alcohol precipitants,freezing or refrigerating before recovery,and diluting broth to enhance cell *** CCS medium produced 14.2 g/L scleroglucan,compared to 10.1 g/L in the modified Wang’s *** on the standard recovery protocol,we determined that 96%of the scleroglucan was recovered from the initial centrifugation and *** the cell pellet with water and recentrifuging only recovered a minimal amount of scleroglucan,and thus it could be eliminated from protocol to save energy and *** cells by boiling or autoclaving did not release more scleroglucan than un-heated samples,and we also found no statistical difference between ethanol,isopopanol,and methanol as scleroglucan *** the broth prior to scleroglucan recovery had no significant effect,while freezing actually decreased scleroglucan *** diluting the broth by 0.50 or 0.34 resulted in the greatest scleroglucan recovery,while

关键词： scleroglucan Sclerotium glucanicum exopolysaccharide separation condensed corn solubles

Aerosol transmission of human pathogens:From miasmata to modern viral pandemics and their preservation potential in the Anthropocene record

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Geoscience Frontiers 2022年第6期13卷 210-223页

作者： Teresa Moreno Wes gibbons Institute of Environmental Assessment and Water research IDAEA-CSIC08034 BarcelonaSpain Bimón Press Sitges08870 BarcelonaSpain

Ongoing uncertainty over the relative importance of aerosol transmission of COVID-19 is in part rooted in the history of medical science and our understanding of how epidemic diseases can spread through human populations. Ancient Greek medical theory held that such illnesses are transmitted by airborne pathogenic emanations containing particulate matter(“miasmata”). Notable roman and medieval scholars such as Varro, Ibn al-Khatib and Fracastoro developed these ideas, combining them with early germ theory and the concept of contagion. A widely held but vaguely defined belief in toxic miasmatic mists as a dominant causative agent in disease propagation was overtaken by the science of 19th century microbiology and epidemiology, especially in the study of cholera, which was proven to be mainly transmitted by contaminated water. Airborne disease transmission came to be viewed as burdened by a dubious historical reputation and difficult to demonstrate convincingly. A breakthrough came with the classic mid-20th century work of Wells, riley and Mills who proved how expiratory aerosols(their “droplet nuclei”)could transport still-infectious tuberculosis bacteria through ventilation systems. The topic of aerosol transmission of pathogenic respiratory diseases assumed a new dimension with the mid-late 20th century “Great Acceleration” of an increasingly hypermobile human population repeatedly infected by different strains of zoonotic viruses, and has taken centre stage this century in response to outbreaks of new respiratory infections that include coronaviruses. From a geoscience perspective, the consequences of pandemic-status diseases such as COVID-19, produced by viral pathogens utilising aerosols to infect a human population currently approaching 8 billion, are far-reaching and unprecedented. The obvious and sudden impacts on for example waste plastic production, water and air quality and atmospheric chemistry are accelerating human awareness of current environmental chal

关键词： COVID-19 History of epidemics Aerosol disease transmission Coronavirus Anthropocene record

Preparation of active carbons from corn stalk for butanol vapor adsorption

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Journal of Energy Chemistry 2017年第1期26卷 35-41页

作者： Yuhe Cao Keliang Wang Xiaomin Wang Zhengrong Gu Tyler Ambrico william gibbons Qihua Fan Al-Ahsan Talukder Agricultural and Biosystems Engineering Department South Dakota State UniversityBrookingsSDUSA Department of Physics and Astronomy Stony Brook UniversityStony BrookNYUSA Department of Biology and Microbiology South Dakota State UniversityBrookingsSDUSA Electrical Engineering and Computer Science Department South Dakota State UniversityUSA

Active carbons(ACs) were prepared through chemical activation of biochar from whole corn stalk(WCS)and corn stalk pith(CSP) at varying temperatures using potassium hydroxide as the activating agent. ACs were characterized via pore structural analysis and scanning electron microscopy(SEM). These adsorbents were then assessed for their adsorption capacity for butanol vapor. It was found that WCS activated at900 °C for 1 h(WCS-900) had optimal butanol adsorption characteristics. The BET surface area and total pore volume of the WCS-900 were 2330 m2/g and 1.29 cm3/g, respectively. The dynamic adsorption capacity of butanol vapor was 410.0 mg/g, a 185.1% increase compared to charcoal-based commercial AC(143.8 mg/g).

关键词： Corn stalk KOH Active carbon Gas stripping Butanol adsorption

Follow the nevus: the cost-utility of monitoring for growth of choroidal nevi

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International Journal of Ophthalmology(English edition) 2019年第9期12卷 1456-1464页

作者： AlexAnder S.Barsam Allister.gibbons Andrew J.McClellan J.william Harbour william E.Smiddy Department of Ophthalmology Bascom Palmer Eye InstituteUniversity of Miami Miller School of MedicineFlorida 33136United States Texas retina Associates Ft.WorthTexas 76104United States

AIM: To develop a model to evaluate the cost-utility of choroidal nevi monitoring recommendations with varying clinical risk ***: A Markov model was created to evaluate the cost-utility in cost per quality-adjusted life-year($/QALY) for monitoring patients with choroidal nevus. This probabilistic model was applied both to a hypothetically monitored and unmonitored group of patients beginning at different ages and with varying clinical risk factors of the nevus. Duration of screening was modeled for the remainder of the patients’ life expectancy. Best available clinical data on the prevalence and incidence of choroidal nevi/melanoma, and relative risk of nevus transformation were combined with the initial and downstream costs of screening, downstream costs of melanoma-related mortality, and QALY saved by monitoring, to estimate the best monitoring regimen. Main outcome measures were average $/QALY saved by consensus recommended monitoring scenarios for the duration of a patient’s remaining life expectancy in comparison with no follow-up, and the cost-utility of modified regimens. rESULTS: The $/QALY of the recommended monitoring scenarios varied substantially based on nevus clinical risk factors, patient age, frequency of follow-up, and objective testing utilized. The $/QALY for the recommended monitoring scenario of a flat nevus without risk factors in a 60-yearold patient was $77 180. The $/QALY for monitoring a nevus with 3 clinical risk factors in a 60-year-old patient was $85 393. The $/QALY values for differently-aged patients were larger, and intermediate degrees of risk factors for nevus growth varied, depending largely upon the specifics of the modeled monitoring ***: The average $/QALY of currently recommended monitoring scenarios fall within economically acceptable standards and could provide insight for formulating appropriate clinical strategies. Cost-utility could be enhanced by targeting higher risk groups and considering l

关键词： cost-utility choroidal nevus choroidal melanoma screening Markov modeling

Does Tenure Security reduce Disaster risk? A Comparative Study of the Nairobi Settlements of Kibera and Kawangware

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International Journal of Disaster risk Science 2021年第4期12卷 445-457页

作者： rónán McDermott Pat gibbons Dalmas Ochieng Charles Owuor Olungah Desire Mpanje Centre for Humanitarian Action University College DublinDublinD04 V1W8Ireland Institute for Anthropology Gender and African StudiesUniversity of NairobiNairobi30197Kenya

While scholarship suggests that improving tenure security and housing significantly reduces disaster risk at the household level within urban settings,this assertion has not been adequately *** security can be conceived as being composed of three interrelated and overlapping forms:tenure security as determined by legal systems;de facto tenure security;and tenure security as perceived by *** article traces the relationship between tenure security,the quality of housing,and disaster risk on the basis of a mixed methods comparative case study of the settlements of Kawangware and Kibera in *** the findings suggest that owner-occupancy is associated with the structural integrity of dwellings to a greater extent than tenantship,no association was found between the length of occupancy by households and the structural integrity of the ***,tenantship is not found to be closely associated with fires and flooding affecting the dwelling as extant scholarship would *** ownership is linked with greater investment and upgrading of property with significant implications for disaster *** findings highlight the complex relationship between tenure security and disaster risk in urban informal settlements and provide impetus for further investigation.

关键词： Disaster risk Fire and flood risk Tenure security Urban hazards Urban informal settlements

Human Beings’Sense of smell^1

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上海翻译 1991年第4期 45-46页

作者： Boyd gibbons

Somerset Maugham2 inquired of one of H·G·Wells’s3 mistresses4 why such a paunchy5, homely6 writer had such success with *** smells of honey, she said. Body odors are the smell of acids produced by bacteria metabolizing skin secretions.7 The most repellent8 odors result from the apocrine glands9, associated with underarm and genital hair10 and activated11 when we’re frightened, excited, or aroused. Men have more and larger apocrine glands than women, blacks more than Caucasians,12 Caucasians more than Orientals.13 Varying skin acidity controls the size of

关键词： smell Human Beings Wells writer honey excited genital women acidity announce

Animals Sense of Smell

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上海翻译 1990年第4期 46-47页

作者： Boyd gibbons

Odors that induce psychological orbehavioral changes in the same species——fright in a catfish^2,sexual arousal in abull—are called pheromones^*** nowheredo such odors have more profound aneffect than among the bees,wasps,ants,and termites^4:Pheromones are the chemicalmessages that these insects use to organizetheir complex *** queen honeybee preserves hermonarchy^5 by exuding^6 an odor thatnhibits worker bees from laying eggs

关键词： sexual laying psychological profound scent mating worker marsh behavioral smell