Starch determination by perchloric acid vs enzymes: evaluating the accuracy and precision of six colorimetric methods

Rose, Robin; Rose, Cathy L.; Omi, Steven K.; Forry, Keith R.; Durall, Daniel M.; Bigg, William L.

doi:10.1021/jf00001a001

Cited by 209 publications

(129 citation statements)

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“…Duckweed was hydrolyzed with 1% H 2 SO 4 , and the starch content was then calculated based on the total sugar content (starch content = glucose content × 0.91). 19,20 The crude protein content was measured as CP = K j N × 6.25, Xiao Yao. 21,22 Cellulose content was measured with spectrophotometry: 10 g of duckweed was placed in 1 L of water, 60 mL of 60% H 2 SO 4 were added, and the plants were left to decompose for 30 min.…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

Use of Duckweed (Landoltia punctata) as a Fermentation Substrate for the Production of Higher Alcohols as Biofuels

Zhao

Juan

et al. 2014

Energy Fuels

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Duckweed (Lemnaceae) is a family of aquatic plants with potential for use as the next generation of alternative energy feedstocks, yet little related information about producing higher alcohols from duckweed has been published. We investigated the process of producing higher alcohols from duckweed via fermentation. Results showed that these plants have a promising future as the basis for developing biofuels. This could be achieved through fermentation by yeasts, producing not only traditional forms of energy such as ethanol but also higher alcohols with high energy yields through bioconversion by Clostridium acetobutylicum, mutant yeast strains, and bioengineered strains of Escherichia coli. The concentrations of butanol and total solvent produced via fermentation by C. acetobutylicum CICC 8012 were 12.03 and 20.03 g/L using acid hydrolysate of duckweed versus 12.33 and 20.05 g/L using enzymatic hydrolysate. The yields obtained of 24.06 g/L ethanol and 680.36 mg/L of isopentanol from duckweed using acid hydrolysate are 15 times higher than what could be obtained through the fermentation of the mutation of yeast. In addition, we were able to obtain yields of 16.27 mg/L butanol, 24.68 mg/L isopentanol, and 195.85 mg/L pentanol from the acid hydrolysate of duckweed via fermentation by the bioengineered strains of E. coli. Our results illustrated that duckweed represent an ideal fermentation substrate: they require only simple pretreatment, without the need for supplementary nitrogen or strengthening with redox agents. This provides a foundation for further development of industrialized biofuel production using duckweed. ■ INTRODUCTIONGiven the widely recognized unsustainability of depending solely on petroleum for development and environmental problems, increasing efforts have been directed at synthesizing biofuels from renewable resources. 1−3 To date, several such renewable sources of energy have been developed, including ethanol from sugar cane, corn, and cassava and biodiesel from various plant oils such as coconut, palm, and rapeseed, which are also the sources of food for people and livestock. The increasing demand for ethanol and other biofuels could contribute to a global food shortage. Given this concern about the competing uses of resources for "food versus fuel", the rising scarcity and price of fossil fuels, and the need to protect global environmental resources and food security, there is an even greater need to find new, renewable, nonfood sources for biofuel production.The use of agricultural waste or byproducts and nonfood crop sources as cheap fermentation substrates to produce biofuels has high economic appeal. 4 Among nonfood crops, duckweed, a family of fast-growing, floating species that represent the world's smallest and simplest flowering plants, has been proposed as an inexpensive, sustainable source of plant biomass for producing biofuels. 5 There are many advantages to using duckweed in this regard, compared to other starch feedstocks such as corn and cassava. 6 First, duckweed h...

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Section: ■ Materials and Methodsmentioning

confidence: 99%

Use of Duckweed (Landoltia punctata) as a Fermentation Substrate for the Production of Higher Alcohols as Biofuels

Zhao

Juan

et al. 2014

Energy Fuels

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“…12 seedlings, clustered together in three groups of four plants, were also harvested for analysis of macronutrients (N, P, K), soluble sugars (SS) and starch (St) content in shoot and root portions. The following analytical procedures were applied: Kjeldhal for N (Kjeltec system 1026, Tecator; Höganas, Sweden), blue-molybdate colorimetry for P, flame photometry for K (Flame photometer 410, Corning Ltd, Essex, England), hydroalcoholic extraction and colorimetric titration with anthrone for soluble sugars [60], and acidic hydrolysis followed by titration with anthrone for starch [55]. A spectrophotometer (UV-1601, Shimadzu, Tokyo, Japan) was used for P, SS and St analysis.…”

Section: Methodsmentioning

confidence: 99%

Effects of temperature on growth and stress hardening development of phytotron-grown seedlings of Aleppo pine (Pinus halepensis Mill.)

Fernández

Royo²,

Gil³

et al. 2003

Ann. For. Sci.

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-One year-old Pinus halepensis seedlings, grown in peat-vermiculite-pine bark mix in 200 cm 3 containers, were moved to a growth chamber and submitted to a progressive decrease of temperature and photoperiod for three months. Morphological parameters and nutrient and non-structural carbohydrate content were measured. Root growth potential, freezing and drought resistance tests were assessed. Although height growth stopped when the minimum temperature fell below 9 ºC, shoot dry weight increased further. Needle potassium concentration and K/N ratio increased progressively and significantly throughout the trial. This may be attributed to potassium accumulation. As height growth stopped, physiological changes were detected in shoot nitrogen and soluble sugar concentrations, root activity and hydraulic conductance maintenance. Nevertheless, cold and drought resistance tests, as well as root regeneration potential, did not reveal any sign of plant stress tolerance until the minimum temperature decreased to 8 ºC and photoperiod to 9 h. This latter temperature may be considered to be the threshold for Pinus halepensis to accumulate the required chilling hours that make seedlings suitable for afforestation purposes. At least, more than 330 chilling hours (£ 8 ºC) are required to reach a minimum level of stress hardiness. The Fv/Fm chlorophyll fluorescence ratio, measured just one day after the freezing test, provides a good estimate of plant frost tolerance.Pinus halepensis / plant quality / stress tolerance / chilling hours / chlorophyll fluorescence / plant nutrition Résumé -Effets de la température sur la croissance et le développement de la résistance au stress de semis de Pin d'Alep (Pinus halepensis Mill.). Des semis de Pin d'Alep (Pinus halepensis), âgés d'un an, croissant sur un mélange de tourbe-vermiculite-écorce de pin dans des containers de 200 cm 3 , ont été mis en place dans une chambre de croissance et soumis, pour une période de 3 mois, à une température et photopériode décroissant progressivement. Des paramètres morphologiques, de nutrition et de teneur carbonée non structurale ont été mesurés. Des tests de potentiel de croissance racinaire, de résistance au froid et à la sécheresse ont été réalisés. Bien que la croissance en hauteur se soit arrêtée lorsque la température minimum eu atteint 9°C, la masse sèche des pousses continue d'augmenter. La concentration en potassium des aiguilles, le rapport K/N augmente progressivement et significativement au cours de l'essai. Ceci peut être attribué à une accumulation de potassium. Lorsque la croissance en hauteur s'est arrêtée, des changements physiologiques ont été constatés pour la concentration en azote et en sucre soluble des pousses, dans l'activité des racines et dans le maintien de la conductance hydraulique. Cependant, les tests de résistance au froid et à la sécheresse, de même que le potentiel de régénération racinaire, ne révélèrent aucun signe de tolérance de la plante au stress jusqu'à ce que la température minimum décroisse à 8°C et la ph...

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“…[27]. Soluble sugar and starch concentrations were determined by the anthrone and the perchloric acid methods, respectively [23,27]. …”

Section: Introductionmentioning

confidence: 99%

Effect of water stress conditioning on the water relations, root growth capacity, and the nitrogen and non-structural carbohydrate concentration of Pinus halepensis Mill. (Aleppo pine) seedlings

et al. 1999

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Starch determination by perchloric acid vs enzymes: evaluating the accuracy and precision of six colorimetric methods

Cited by 209 publications

References 20 publications

Use of Duckweed (Landoltia punctata) as a Fermentation Substrate for the Production of Higher Alcohols as Biofuels

Use of Duckweed (Landoltia punctata) as a Fermentation Substrate for the Production of Higher Alcohols as Biofuels

Effects of temperature on growth and stress hardening development of phytotron-grown seedlings of Aleppo pine (Pinus halepensis Mill.)

Effect of water stress conditioning on the water relations, root growth capacity, and the nitrogen and non-structural carbohydrate concentration of Pinus halepensis Mill. (Aleppo pine) seedlings

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