Effects of marine algal proximate composition on methane yields

The suitability of differentGracilaria spp. and twoSargassum species for bioconversion to methane was determined through bioassays of methane yield.Gracilaria species and strains were excellent feedstocks for high methane yields, ranging from 0.28 to 0.40 m³ kg^–1 volatile solids added. These yields ranged from 58 to 95% of theoretical stoichiometric yields. Methane yields were highly correlated with acid soluble carbohydrate components of theGracilaria spp. BothSargassum fluitans andS. pteropleuron were poor feedstocks, with methane yields ranging from 0.12 to 0.19 m³ kg^–1 volatile solids added, 27 to 46% of theoretical stoichiometric yields, respectively. The various tissue types of theseSargassum species were also poor feedstocks for anaerobic digestion to methane. While there is no clear explanation for the low methane yields, the twoSargassum spp. appear to contain a high proportion of an insoluble, non-extractable component which may not be available as a substrate for bioconversion to methane.     

Changing forest water yields in response to climate warming: results from long‐term experimental watershed sites across North America

Climate warming is projected to affect forest water yields but the effects are expected to vary. We investigated how forest type and age affect water yield resilience to climate warming. To answer this question, we examined the variability in historical water yields at long‐term experimental catchments across Canada and the United States over 5‐year cool and warm periods. Using the theoretical framework of the Budyko curve, we calculated the effects of climate warming on the annual partitioning of precipitation (P) into evapotranspiration (ET) and water yield. Deviation (d) was defined as a catchment's change in actual ET divided by P [AET/P; evaporative index (EI)] coincident with a shift from a cool to a warm period – a positive d indicates an upward shift in EI and smaller than expected water yields, and a negative d indicates a downward shift in EI and larger than expected water yields. Elasticity was defined as the ratio of interannual variation in potential ET divided by P (PET/P; dryness index) to interannual variation in the EI – high elasticity indicates low d despite large range in drying index (i.e., resilient water yields), low elasticity indicates high d despite small range in drying index (i.e., nonresilient water yields). Although the data needed to fully evaluate ecosystems based on these metrics are limited, we were able to identify some characteristics of response among forest types. Alpine sites showed the greatest sensitivity to climate warming with any warming leading to increased water yields. Conifer forests included catchments with lowest elasticity and stable to larger water yields. Deciduous forests included catchments with intermediate elasticity and stable to smaller water yields. Mixed coniferous/deciduous forests included catchments with highest elasticity and stable water yields. Forest type appeared to influence the resilience of catchment water yields to climate warming, with conifer and deciduous catchments more susceptible to climate warming than the more diverse mixed forest catchments.     

Optimization of the medium and conditions for cultivatingErwinia sp., a producer of fumarase and aspartase

Mathematical methods of experimental design were used to determine the optimal concentrations of nutrient medium components, aeration conditions, and pH providing for the maximum biomass yields, as well as fumarase and aspartase activities, during submerged cultivation ofErwinia sp. The data showed that different concentrations of carbon source (molasses) and pH of the nutrient medium were required to reach the maximum yields of fumarase and aspartase. Calculations suggested that the combination of these optimized factors would result in 3.2-, 3.4-, and 3.8-fold increases in theErwinia sp. biomass, aspartase activity, and fumarase activity yields, respectively. The experimental data were consistent with these estimates to 80% accuracy.     

The cellulose contents of Indian seaweeds

Cellulose content as well as alpha (α) and beta (β) celluloses were evaluated in 21 seaweed species belonging to different classes growing in Indian waters. The greatest yields of cellulose (crude) and β-cellulose were obtained from Caulerpa taxifolia (approx. 11.0% and 5.2%, respectively), whilst α-cellulose (approx. 8.2%) was the greatest in Padina tetrastromatica. The lowest cellulose (crude), α- and β- contents were recorded from the calcareous red alga Liagora ceranoides (approx. 0.85%, 0.62% and 0.18%, respectively). There was no variation in the yields of cellulose in the brown algae, whilst wide variations in the yields were found in the green and red algae.     

Preparation of o-palmitoyl alkyl lactates through lipase atalysis

Preparation of o-palmitoyl alkyl lactates with methyl, ethyl, propyl, isopropyl and butyl lactates were attempted in a complex esterification reaction using lipases as catalysts. Compared to lactic acid, alkyl lactates were found to be less inhibitory in nature as they resulted in slightly better yields at shake-flask level. Of the alkyl lactates tested, butyl lactate showed better esterification. Porcine pancreas lipase gave higher yields of esters than Rhizomucor miehei lipase (Lipozyme IM20).     

Growth yields of Desulfotomaculum orientis with hydrogen in chemostat culture

Desulfotomaculum orientis (strain Singapore 1) was grown autotrophically with H₂+CO₂ and sulfate, thiosulfate or sulfite as electron acceptor in sulfide- and pH-controlled continuous culture. Under sulfate-limiting conditions real growth yields of up to 9.7 g cell dry mass per mol sulfate were obtained. Electron acceptor limitation resulted in the excretion of up to 14.5 mmol acetate per liter, formed by reduction of CO₂ with H₂. Acetate production was not coupled to an increase of growth yields: under hydrogen-limiting conditions only 1.6 mmol acetate per liter was produced, and even higher growth yields of up to 12,4 g cell dry mass per mol sulfate were obtained. With thiosulfate or sulfite as electron acceptor growth yields increased up to 17.9 g cell dry mass per mol electron acceptor. Growth yields were not simply correlated with the growth rate, and did not allow the determination of maintenance coefficients and the extrapolation to maximal yields at infinite growth rate (Y ^max). The maximal growth rates (_max) with sulfate and thiosulfate were 0.090 and 0.109 h^-1, respectively, if cells were grown continuously in sulfidostat culture under nonlimiting conditions.The net energy yield of sulfate reduction and the energy requirement for the activation of sulfate by Desulfotomaculum orientis are discussed.     

Bacillus licheniformis protease-catalyzed peptide synthesis via the kinetically controlled approach using the carbamoylmethyl ester as an acyl donor in anhydrous acetonitrile

Summary The couplings ofN-protected amino acid esters with amino acid amides proved to be carried out in anhydrous acetonitrile in the presence ofBacillus licheniformis protease (subtilisin Carlsberg) immobilized on Celite. The maximal peptide yields were obtained with the immobilized enzyme prepared through lyophilization from a pH 10.7 buffer solution. A series of dipeptide syntheses and several segment condensations were achieved generally in high yields by the combined use of the immobilized enzyme prepared from this pH and the carbamoylmethyl ester as the acyl donor.     

Bacillus licheniformis protease-catalyzed peptide synthesis via the kinetically controlled approach using the carbamoylmethyl ester as an acyl donor in anhydrous acetonitrile

The couplings of N-protected amino acid esters with amino acid amides proved to be carried out in anhydrous acetonitrile in the presence of Bacillus licheniformis protease (subtilisin Carlsberg) immobilized on Celite. The maximal peptide yields were obtained with the immobilized enzyme prepared through lyophilization from a pH 10.7 buffer solution. A series of dipeptide syntheses and several segment condensations were achieved generally in high yields by the combined use of the immobilized enzyme prepared from this pH and the carbamoylmethyl ester as the acyl donor.     

The effects of nematode resistant and susceptible spring oat cultivars and aldicarb on the cereal cyst nematode Heterodera avenae and yields in contrasting soil types

The effects of the cereal cyst-nematode, Heterodera auenae Woll. on resistant and susceptible oat cultivars, with and without aldicarb treatment, were compared on a clay-with-flints soil at Rothamsted and a loamy sand at Woburn. At both sites, when H. auenae was extremely scarce, yields were not further enhanced by aldicarb. At Rothamsted aldicarb increased yields by 48–72% when H. auenae averaged 10 eggs/g soil. At Woburn, aldicarb increased yields of both susceptible and resistant varieties by 80–90% with 20 eggs/g. The resistant varieties conferred yield benefits in the following oat crop equal to the residual effects of aldicarb applied before the previous crop, demonstrating that H. auenae was wholly responsible for the yield losses. Nematode resistant oats suffered as much or more damage from root invasion by H. auenae juveniles as the susceptible varieties but the resulting decrease in nematode numbers led to considerable yield improvements in the following year. At Woburn in 1977, when formalin was an added treatment, fewer females were infected by parasitic fungi and post-crop egg numbers were greater.     

Influence of precursors and additives on microbial lipases stabilized by sol-gel entrapment

Sol-gel entrapment of microbial lipases from Candida cylindracea (Cc lipase),Pseudomonas fluorescens (Lipase AK), and Pseudomonas cepacia (Lipase PS), using as precursors tetraethoxysilane (TEOS) and silanes of type R-Si(OEt)₃ with alkyl or aryl R groups, has been investigated. Three different methods using these precursors were tried exhibiting protein immobilization yields in the range of 20–50%. Hydrolysis of emulsified olive oil, esterification of lauric acid with 1-octanol and enantioselective acylation of 2-pentanol have been used as model reactions for testing the properties of the encapsulated lipases. The recovery yields of the enzyme activity in the esterification reaction were between 20–68%, the best performance being achieved with phenyltriethoxysilane and tetraethoxysilane precursors at 3:1 molar ratio. When testing the entrapped Lipase AK in the enantioselective acylation reaction of 2-pentanol, activity recovery yields up to 32% related to the free enzyme were obtained and the immobilization increased the enantioselectivity of the enzyme.     

In situ lipase-catalyzed reactive extraction of oilseeds with short-chained dialkyl carbonates for biodiesel production

Dimethyl/diethyl carbonate was adopted as extraction solvent and transesterification reagent at the same time for in situ lipase-catalyzed reactive extraction of oilseeds for biodiesel production in this work. Fatty acid methyl esters and ethyl esters were respectively obtained with higher yields than those achieved by conventional two-step extraction/transesterification. The augment ranged from 15.7% to 31.7%. The key parameters such as solvent/seed ratio and water content were further investigated to find their effects on the in situ reactive extraction. The highest yields of Pistacia chinensis Bunge methyl ester, P. chinensis Bunge ethyl ester, Jatropha curcas L methyl ester and J. curcas L ethyl ester could attain 89.6%, 90.7%, 95.9% and 94.5%, respectively under the optimized conditions.     

Synthesis of New exo‐ and endo‐3,8‐Dihydro‐β‐santalols and Other Norbornyl‐Derived Alcohols

Several new and differently functionalized cis‐2,3‐dimethylnorbornane derivatives presenting diverse side‐chain lengths were prepared, the structures of which are related to the natural fragrance β‐santalol. In particular, exo‐ and endo‐3,8‐dihydro‐β‐santalols, with either (E) or (Z) C?C‐bond configuration on the side chain, were synthesized in seven steps and 21–24% overall yields. Several other exo‐ and endo‐norbornyl alcohols with shorter side chains were also prepared in high yields. The olfactory evaluation indicated woody, sandalwood, as well as fruity notes for some of the derivatives.     

Tissue degradation and enzymatic activity observed during protoplast isolation in two ornamental <Emphasis Type="Italic">Grevillea</Emphasis> species

Summary Degradative changes in tissue during protoplast isolation were a contributing factor to low protoplast yields in the saltsensitive Grevillea arenaria (R. Brown) and the salt-tolerant Grevillea ilicifolia (R. Brown). Protein and malondialdehyde content decreased significantly during the protoplast isolation procedure. Acid and neutral proteases were identified, and high acid protease activities were correlated to low protoplast yields. Acid phosphatase, catalase, polyphenol oxidase and lipoxygenase activities increased in both Grevillea species with cell wall digestion. High activities of catalase and low levels of polyphenol oxidase were correlated with high protoplast yields. Levels of acid phosphatase and lipoxygenase were not good indicators of final protoplast yields. The addition of the anti-oxidant, reduced glutathione, and the acid protease inhibitor, pepstatin A, significantly increased protoplast yields. Strategies were identified to minimize deleterious degradative effects during the isolation of protoplasts, including strict pH control, testing a number of cell wall digestion enzymes, and the addition of anti-oxidative metabolites and protease inhibitors.     

Efficiency of Repeated Phytoextraction of Cadmium and Zinc from an Agricultural Soil Contaminated with Sewage Sludge

Long-term application of sewage sludge resulted in soil cadmium (Cd) and zinc (Zn) contamination in a pot experiment conducted to phytoextract Cd/Zn repeatedly using Sedum plumbizincicola and Apium graceolens in monoculture or intercropping mode eight times. Shoot yields and soil physicochemical properties changed markedly with increasing number of remediation crops when the two plant species were intercropped compared with the unplanted control soil and the two monoculture treatments. Changes in soil microbial indices such as average well colour development, soil enzyme activity and soil microbial counts were also significantly affected by the growth of the remediation plants, especially intercropping with S. plumbizincicola and A. graveolens. The higher yields and amounts of Cd taken up indicated that intercropping of the hyperaccumulator and the vegetable species may be suitable for simultaneous agricultural production and soil remediation, with larger crop yields and higher phytoremediation efficiencies than under monoculture conditions.     

Growth,ionic balance,proton excretion,and nitrate reductase activity in Alnus and Hippophaë supplied with different sources of nitrogen

Summary Pre-cultivated, nodulated and non-nodulated plants of black alder (Alnus glutinosa) and sea buckthorn (Hippophaë rhamnoides ssp.rhamnoides) were grown on different N sources, with and without acidity control. Dry matter yields were lowest when plants were supplied with only NO ₃ ^– and were much greater when NH ₄ ⁺ was supplied either alone or in combination with NO ₃ ^– as long as the external pH was controlled; the final yields of the N₂-fixing plants were relatively low, especially withH. rhamnoides. Without acidity control, yields were greatly reduced in the presence of NH ₄ ⁺ .Proton or hydroxyl-ion effluxes, calculated on the basis of plant analyses, agreed well with measured excretion values. Without pH adjustment, the total proton efflux into the external solution was greater inA. glutinosa than inH. rhamnoides.Both species, but particularlyA. glutinosa, displayed the highest nitrate reductase activity in the roots.     

Bioassays using Stigeoclonium tenue Kütz. and Scenedesmus quadricauda (Turp.) Bréb. as testorganisms; a comparative study

Three different bioassays, two culture tube test methods with respectively Stigeoclonium tenue or Scenedesmus quadricauda and one bottle test with S. quadricauda, were compared. The yields obtained in the various tests were linearily correlated (r = 0.86, P < 0.001). The same primary limiting nutrient was indicated by the bioassays in most cases. However the algal growth in the tube test using Stigeoclonium was more often P-limited. In the case of S. quadricauda both test methods (tube and bottle) were nearly equally effective. The yields of N-limited samples were significantly correlated with the inorganic-N as well as total-N concentration of the water sample. A significant correlation of the ortho-P as well as total-P concentration with the yield of the P-limited assays was only found for Stigeoclonium tenue. The critical total N/P ratio (by weight) for N or P limitation was approximately 17: 1 for Stigeoclonium tenue and 22: 1 for Scenedesmus quadricauda.     

Seasonal variation in Laminaria digitata and its impact on biochemical conversion routes to biofuels

Laminaria digitata is a highly prevalent kelp growing off the coast of the UK but has rarely been considered as a source of biomass to date. This study shows it can be used as a feedstock in both ethanol fermentation and anaerobic digestion for methane production. The study optimised several parameters in the fermentation of L. digitata and investigated the suitability of the macroalgae through the year using samples harvested every month. For both methane and ethanol production, minimum yields were seen in material harvested in March when the carbohydrates laminarin and mannitol were lowest. July material contained the highest combined laminarin and mannitol content and maximum yields of 167 mL ethanol and 0.219 m³ kg⁻¹L. digitata.     

Utilization of normal alkanes by yeasts

A stable mixed yeast culture designated as Culture 4, consisting of Candida intermedia and Candida lipolytica was investigated. The culture was judged stable based on uniformity of fermentation results and the nearly constant ratio of the two organisms at the completion of fermentations. However, the ratio of the two organisms at different times during the fermentation was not determined. The mixed culture grew more rapidly on n-alkanes than did C. intermedia; C. lipolytica did not grow on unsupplemented mineral salt–n-alkane medium. Solid n-alkanes were dissolved in 2,6,0,14-tetramethylpentadecane (pristane) for investigation as carbon sources. With Culture 4, on n-alkanes ranging from pentadecane (C₁₅) through octacosane (C₂₈), cell yields were 74.2–89.5%; generation times were 3.0–8.0 hr. during the exponential growth phase. The fastest growth rates and highest cell yields were obtained with docosane (C₂₂) as substrate. The cells obtained contained 6.75–8.81% nitrogen and 1.9–13.4% lipid. Crude protein yields were 34.4–47.6%. The oxidation of n-alkanes by C. intermedia was studied manometrically with resting whole cells. The alkaneoxidizing system of this organism appears to be constitutive and nonspecific for alkane substrates.     

On the role of orientation in reducing photoinhibitory damage in photosynthetic-twig desert shrubs

Quantum yields for O₂ evolution were measured in photosynthetic twigs and leaves of Hymenoclea salsola and Senecio douglasii, two common shrubs of the deserts of western North America. When exposed to long-term drought, quantum yields of leaves and twigs remained constant up to the point of leaf abscision in both species. As water stress developed further, quantum yields began to decline in twigs; the extent of this quantum yield reduction was dependent on incident photon flux density. The reduction in quantum yield in twigs, which have a near-vertical orientation, was greatly accelerated when twigs were reoriented to the near-horizontal inclination typical of leaves. The reductions in quantum yield were not rapidly reversible and are interpreted as indicating photoinhibitory damage. The results are discussed in terms of the role that a near-vertical orientation might serve in maintaining photosynthetic structures through a drought period.     

Comparative Growth,Biomass Production and Fuel Properties Among Different Perennial Plants,Bamboo and <Emphasis Type="Italic">Miscanthus</Emphasis>

Bamboo and Miscanthus species are perennial low-input plants that are excellent candidates for bioenergy feedstock production. Biological characteristics, dry matter yields and fuel properties of the bamboo and Miscanthus have been studied. Genotype growth characteristics were determined by measurements of plant height, tillering, tuft diameter, and shoot diameter. To date, comparisons of biomass yields of bamboo and Miscanthus have not been previously reported in the literature. Bamboo and Miscanthus species were collected and previous articles describing the productivity of bamboo and Miscanthus were examined. Genotypes differed in plant height, tillering, tuft diameter, and shoot diameter. Nitrogen, temperature, water and plant density have effects on mature stands biomass production, which ranged from 5.9 to 49.5 tonnes/ha/yr for bamboo and 3.2 to 49.0 tonnes/ha/yr for Miscanthus. With such biomass yields, bamboo and Miscanthus should be considered as two very promising plants for biomass production in Zhejiang, China in the near future.