Maximum Sugar Concentration Research Articles

Effects of presowing gamma irradiation on the photosynthetic pigments, sugar content and carbon gain of Cullen corylifolium (L.) Medik

To determine the effects of gamma radiation on the photosynthetic pigments, sugar content and total carbon gain, seeds of Cullen corylifolium (L.) Medik. were irradiated with variable doses (0, 2.5, 5, 10, 15, and 20 kGy) at the rate of 1.65 kGy h-1 from 60Co gamma source. Cullen corylifolium represents an important Chinese medicine with adequate levels of secondary metabolites, thus we hypothesized that gamma irradiation could modulate primary metabolites which could supplement secondary metabolite levels. The seeds were then transferred to field for biochemical analysis at different developmental stages; pre-flowering, flowering and post-flowering. Gamma dosage at 10 kGy resulted in a significant increase in concentration of chlorophyll a (61.17%), chlorophyll b (93.18%) and total chlorophyll (71.66%), suggesting that low doses of radiation could activate photosynthetic pigment system while at 15 and 20 kGy dose resulted in depletion of such parameters. Sugar and total C analysis of plants irradiated at 10 kGy demonstrated significantly maximum (216.01%) sugar content in leaves at all developmental stages and significantly minimum (46.13%) and (57.81%) in plants raised from seeds irradiated at 15 and 20 kGy respectively. Effective stimulatory dose for C. corylifolium ‘11062’ is 10 kGy. In contrast, the carotenoid content of the plants exposed to 15 and 20 kGy was maximum than control. Significance of such stimulation correlated with increasing C mass of the plant concerned is discussed in the light of newer aspects in research.

Synthesis of titanium containing MCM-41 and its application for catalytic hydrolysis of cellulose

Titanium containing MCM-41 is synthesized hydrothermally in the presence of structure-directing agent cetyltrimethylammonium bromide (CTAB). Bi- and tri-metal Fe and Zn are impregnated in these materials to improve the acid catalytic sites as well. XRD, BET nitrogen adsorption isotherm, TEM and SEM analysis confirm the presence of mesopores in the composite. The local environment of titanium incorporated into the mesoporous silicate material is investigated by FT-IR and UV–Vis spectroscopy. These results indicate the presence of active centers within the composite material Ti, Fe and Zn. The new composite materials are preliminarily tested in the hydrolysis of cellulose. All the titanium MCM-41 materials improve the conversion of cellulose, providing higher catalytic activity in hydrolysis. There is maximum sugar and 5-HMF concentration resulted from hydrolysis of cellulose with Fe/Ti-MCM-41 catalyst.

Optimization of sono-assisted dilute sulfuric acid process for simultaneous pretreatment and saccharification of rice straw

In this study, sono-assisted dilute sulfuric acid process was evaluated for its viability of simultaneous pretreatment and saccharification of rice straw. Three critical factors for simultaneous pretreatment and saccharification process, such as sonication time (30–50 min), temperature (70–90 °C), and acid concentration (5–10 %), were optimized to maximize reducing sugar yield using Box-Behnken design and response surface methodology. The response surface methodology model was found to be adequately fitted to the obtained data. Simultaneous pretreatment and saccharification factors were optimized at sonication of 50 min, 80 °C and an acid concentration of 10 % yielding the maximum sugar content (31.78 g/100 g of biomass). Scanning electron microscopy revealed that the smooth surface of raw biomass was altered into a rough and porous surface as a result of sugar release, which showed the prospective feasibility of simultaneous pretreatment and saccharification process. This process integration may lead to develop economical bioethanol production facility. However, further research is required to make this process industrially viable.

Nectar sugar production across floral phases in the Gynodioecious Protandrous Plant Geranium sylvaticum [corrected

Many zoophilous plants attract their pollinators by offering nectar as a reward. In gynodioecious plants (i.e. populations are composed of female and hermaphrodite individuals) nectar production has been repeatedly reported to be larger in hermaphrodite compared to female flowers even though nectar production across the different floral phases in dichogamous plants (i.e. plants with time separation of pollen dispersal and stigma receptivity) has rarely been examined. In this study, sugar production in nectar standing crop and secretion rate were investigated in Geranium sylvaticum, a gynodioecious plant species with protandry (i.e. with hermaphrodite flowers releasing their pollen before the stigma is receptive). We found that flowers from hermaphrodites produced more nectar than female flowers in terms of total nectar sugar content. In addition, differences in nectar production among floral phases were found in hermaphrodite flowers but not in female flowers. In hermaphrodite flowers, maximum sugar content coincided with pollen presentation and declined slightly towards the female phase, indicating nectar reabsorption, whereas in female flowers sugar content did not differ between the floral phases. These differences in floral reward are discussed in relation to visitation patterns by pollinators and seed production in this species.

Bioethanol production from Scenedesmus obliquus sugars: the influence of photobioreactors and culture conditions on biomass production

A closed-loop vertical tubular photobioreactor (PBR), specially designed to operate under conditions of scarce flat land availability and irregular solar irradiance conditions, was used to study the potential of Scenedesmus obliquus biomass/sugar production. The results obtained were compared to those from an open-raceway pond and a closed-bubble column. The influence of the type of light source and the regime (natural vs artificial and continuous vs light/dark cycles) on the growth of the microalga and the extent of the sugar accumulation was studied in both PBRs. The best type of reactor studied was a closed-loop PBR illuminated with natural light/dark cycles. In all the cases, the relationship between the nitrate depletion and the sugar accumulation was observed. The microalga Scenedesmus was cultivated for 53days in a raceway pond (4,500L) and accumulated a maximum sugar content of 29% g/g. It was pre-treated for carrying out ethanol fermentation assays, and the highest ethanol concentration obtained in the hydrolysate fermented by Kluyveromyces marxianus was 11.7g/L.

Kinetic study of batch and fed-batch enzymatic saccharification of pretreated substrate and subsequent fermentation to ethanol

BackgroundEnzymatic hydrolysis, the rate limiting step in the process development for biofuel, is always hampered by its low sugar concentration. High solid enzymatic saccharification could solve this problem but has several other drawbacks such as low rate of reaction. In the present study we have attempted to enhance the concentration of sugars in enzymatic hydrolysate of delignified Prosopis juliflora, using a fed-batch enzymatic hydrolysis approach.ResultsThe enzymatic hydrolysis was carried out at elevated solid loading up to 20% (w/v) and a comparison kinetics of batch and fed-batch enzymatic hydrolysis was carried out using kinetic regimes. Under batch mode, the actual sugar concentration values at 20% initial substrate consistency were found deviated from the predicted values and the maximum sugar concentration obtained was 80.78 g/L. Fed-batch strategy was implemented to enhance the final sugar concentration to 127 g/L. The batch and fed-batch enzymatic hydrolysates were fermented with Saccharomyces cerevisiae and ethanol production of 34.78 g/L and 52.83 g/L, respectively, were achieved. Furthermore, model simulations showed that higher insoluble solids in the feed resulted in both smaller reactor volume and shorter residence time.ConclusionFed-batch enzymatic hydrolysis is an efficient procedure for enhancing the sugar concentration in the hydrolysate. Restricting the process to suitable kinetic regimes could result in higher conversion rates.

Pretreatment of Corn Stover Silage with Fe(NO3)3 for Fermentable Sugar Production

Corn stover silage is an attractive raw material for the production of biofuels and chemicals due to its high content of carbohydrates and easy degradability. The effects of Fe(NO(3))(3) pretreatment conditions on sugar yields were investigated for corn stover silage. In addition, a combined severity factor was used to evaluate the effect of pretreatment conditions on the concentration of total sugars and inhibitors. Optimum pretreatment condition was obtained at 150°C for 10min with 0.05M Fe(NO(3))(3), at which the yields of soluble xylose and glucose in liquid achieved 91.80% of initial xylose, 96.74% of initial arabinose and 19.09% of initial glucose, respectively, meanwhile, 91.84% of initial xylose, 98.24% of initial arabinose, and 19.91% of initial glucose were removed. In addition, a severity analysis showed that the maximum sugar concentration of 33.48g/l was achieved at combined severity parameter value of 0.62, while the inhibitor concentration was only 0.03g/l. Fe(NO(3))(3) is an effective catalyst to enhance hemicellulose hydrolysis in corn stover silage, the yields of monomeric xylose in the liquid fraction reached as high as 91.06% of initial xylose and 96.22% of initial arabinose, respectively.

Research on Enhanced Straw Saccharification Technology of Hydrogen Production

Straw has a complex structure composed mainly by cellulose, hemicellulose and lignin, resulting in the difficulty to use it as the substrate for hydrogen production directly. Hydrogen production from saccharification plant straw was performed in this study. The effect of experimental time and temperature on saccharification efficiency of the straw was investigated in this work. The results show that efficiency of saccharification by hydrochloric acid on plant straw is better than that by acetate due to the different extent of acid ionization. The maximum sugar content of 36.8 Brix and 35.4 Brix was acquired at the experimental time of 1h and temperature of 20°C with the corresponding hydrogen yield of 0.02mlH2/L saccharification liquid and 0.0182mlH2/L saccharification liquid by bacteria SUES-1, respectively.

Kinetic Study on the Pretreatment and Enzymatic Saccharification of Rice Hull for the Production of Fermentable Sugars

The production of fermentable sugars from rice hull was studied by dilute acid pretreatment and enzymatic saccharification. Rice hull (15%, w/v) was pretreated by 1% (v/v) sulfuric acid at high temperature (120 approximately 160 degrees C) for 15, 30, 45, and 60 min, respectively. The maximum sugar concentration from rice hull in the prehydrolysate was obtained at 140 degrees C for 30 min, but the enzymatic saccharification yield from the corresponding pretreated rice hull is not high. To another aspect, the maximum enzymatic saccharification yield was achieved at 160 degrees C for 60 min, while the recovery of fermentable sugars was the poorest. To take account of fermentable sugars from pretreatment and enzymatic saccharification, the maximum yield of sugars was obtained only when rice hull was treated at 140 degrees C for 30 min. Under this condition, 72.5% (w/w) of all sugars generated from the raw material can be recovered. The kinetic study on the enzymatic saccharification of dilute acid pretreated rice hull was also performed in this work by a modified Michaelis-Menten model and a diffusion-limited model. After calculation by a linear and a non-linear regression analysis, both models showed good relation with the experimental results.

Production of Oligosaccharide from Alginate Using Pseudoalteromonas agarovorans

A marine bacterium was isolated from seawater near the Korean south coast for efficient saccharification from alginate. Based on 16S rDNA sequence, the isolated strain was identified as Pseudoalteromonas agarovorans. Various environmental factors affecting saccharification of alginate using P. agarovorans CHO-12 have been investigated in flask cultures. The optimum concentration of sugar was obtained at 30 rpm and 29 degrees C. Among various NaCl concentrations, when NaCl concentration was increased from 10 to 30 g/l, the cell concentration sharply increased, while there is no increase at above 40 g/l. The maximum sugar concentration was obtained at 13.8 when 30 g/l of NaCl was used. Yeast extract and corn steep liquor were the best nitrogen source for efficient saccharification. Especially, the sugar concentration of 14.9 g/l was obtained after 3 days of culture using a mixture of 1.0 g/l of yeast extract and 1.5 g/l of corn steep liquor. Scale up was carried out at 50 l of reactor for 3 days using P. agarovorans CHO-12 and Stenotrophomonas maltophilia sp. When S. maltophilia was used, cell concentration was about twofold higher than that of P. agarovorans CHO-12. On the other hand, when P. agarovorans CHO-12 was used, the maximum saccharification rate was obtained, 7.5 g/l/day after 2 days of culture, which was about tenfold higher than that of S. maltophilia.

Studies on Saccharification from Alginate using Stenotrophomonas maltophilia

Various environmental factors affecting saccharification from alginate using Stenotrophomonas maltophilia were investigated in flask cultures. The cell concentrations increased from 0.6 to 0.92 optical density (OD) at 660 nm when the agitation rate increased from 15 to 90 rpm. On the other hand, the maximum concentration of sugar was obtained at 3.8 g/l after 4 days of culture at 15 rpm. After 3 days of preculture at 33 °C, the sugar concentration peaked at 5.0 g/l after 5 days of culture. When 10 g/l of NaCl was used, the maximum concentration of sugar, 5.3 g/l, was obtained after 5 days of culture. Yeast extract and peptone were the best nitrogen source for effective saccharification. Especially, the sugar concentration was 6.1 g/l after 5 days of culture using a mixture of 1.0 g/l of yeast extract and 1.0 g/l of peptone. Under optimum conditions of culture and media, scale-up for effective saccharification from alginate was carried out in 5 l flasks. The cell concentration after 2 days of culture was 0.61 OD at 660 nm and showed no further increase after 3 days of culture. The sugar concentrations from alginate were increased with increasing culture time to 7.9 g/l after 9 days of culture.

THE CONDUCT OF SOME SELECTED YEASTS STRAINS UNDER THE INFLUENCE OF SOME EXOGENOUS FACTORS

SUMMARY It is already known the fact that in the spontaneou s fermentation that is produced in the sowing absence with the selection yeasts, the indig ene micro flora assures the fermentation process (2). Although the Saccharomyces cerevisiae species with her grate variety is not dominated on the grape surface, when it grows the a lcohol contain of the fermentation must, the yeasts indigene of Saccharomyces type become predominant and ensures the fermentation ending. In the present study, after th e selection of the present yeast strains in the spontaneous micro flora, the identification and the systematic integration of the isolated (1), we have passed to the second level: the conduct che ck of the strains in different environmental conditions (temperature, sugar concentration, and the SO 2 doses). All the tests have been made in comparison with natural fermentation of grape must, separated for each strain. The strains that belong to the Saccharomyces ellipsoideus strain from the spontaneous micro flora show o good fermentation activity when the fermentation temperature is between 18 and 25°C and the maximum sugar concentration from the environment is under 250g/l. The natural concentration that was made in the same environmental conditions show a higher prefermentation and fermentation period and a lower maximum of sugar metabolic process in comparison with the fermentation inducted in the se lection strains. When the grapes were sulfated as a result of a crop that was stroked wit h mould the natural fermentation is developing very slow, so it is required a use of th e selection yeasts, that prove to be very useful in those conditions.

Cane yield and quality characters of some promising somaclonal variants of sugarcane

Six tissue culture derived sugarcane somaclones TC-434, TC-435, TC-436, TC-237 and TC-045 from CoC671 and somaclone number TC-338 from Co7219 developed by Biotechnology section of Vasahtdada Sugar Institute, Pune were evaluated for their agronomical and quality attributes during suru season. Somaclone TC-435 gave higher cane yield at 12 months crop age over CoC 671. Somaclone TC-435 had significantly higher millable cane height and number of internodes than that of donor parent CoC671 .Tillering ratio at 120 days was found to be significantly higher in somaclones TC-434 and TC-045 as compared to the donor parent CoC 671. Somaclones TC-045 and TC-434 had maximum sugar content, showing increasing trend from 10th to 12th month crop age. Brix value about 23 was recorded in somaclones TC-237, TC-436 and TC-434 at the age of 12 months. Increasing trend in sugar recovery from 10th month onward was found in somaclones TC-045, TC-434 and TC-435 indicating their earliness in sugar recovery and suitability for early crush if planted in sum season. These somaclones showed higher values of CCS i.e., more than 15 % at 12 months. The promising somaclones are being evaluated in different agro-climatic zones.

Rootless Aquatic Plant Aldrovanda Vesiculosa: Physiological Polarity, Mineral Nutrition, and Importance of Carnivory

Various ecophysiological investigations are presented in Aldrovanda vesiculosa, a rootless aquatic carnivorous plant. A distinct polarity of N, P, and Ca tissue content per dry mass (DM) unit was found along Aldrovanda shoots. Due to effective re-utilization, relatively small proportions of N (10 - 13 %) and P (33 - 43 %) are probably lost with senescent leaf whorls, while there is complete loss of all Ca, K, and Mg. The total content of starch and free sugars was 26 - 47 % DM along adult shoots, with the maximum in the 7th - 10th whorls. About 30 % of the total maximum sugar content was probably lost with dead whorls. The plant was found to take up 5 - 7 times more NH4+ to NO3- from a mineral medium. Under nearly-natural conditions in an outdoor cultivation container, catching of prey led to significantly more rapid growth than in unfed plants. DM of the fed controls was 48 % higher than in the unfed plants. The controls produced 0.69 branches per plant, while the unfed plants did not produced any. However, the N and P content per DM unit increased by 6 - 25 % in the apices and the first 6 whorls in the unfed variant, as compared to the fed controls. It may be suggested that carnivory is very important for Aldrovanda.

Relationship between surface color and other maturity indices in wild lowbush blueberries

The surface color, size, and sugar, titratable acid and anthocyanin contents were measured on samples of various maturities from 72 individual lowbush blueberry clones to determine the relationships between surface color and other ripeness indicators. Among the total 504 berries, the maximum sugar content was approximately 5 times that of the minimum, while the maximum titratable acid and anthocyanin contents were 20 and 11 times those of the minimum contents, respectively. Correlations among variates were generally strongest for samples within clones, and they were weakest among the variate means for the 72 clones. For the total 504 berries, sugar content correlated more strongly with surface color than with berry size, while acid content correlated similarly with surface color and size. Correlations (positive or negative) among berry size and sugar and titratable acid contents did not exceed 0.60. Principal component analysis, which was used to identify groupings of correlated variates, indicated coordinated changes in berry characteristics during ripening, lower sugar and anthocyanin concentrations in large berries, and substantial interclonal variation in wild blueberries. Clonal selections obtained from an experimental trial differed significantly in all the variates measured, while wild clones without a surface bloom were not different from those clones with bloom. Key words: Lowbush blueberry, Vaccinium angustifolium, color, sugar, titratable acid, anthocyanin

Role of pectolytic enzymes in the development of woolliness in peaches

SummaryThe role of pectolytic enzymes in the development of woolliness in peaches (Prunus persica, cv. Peregrine), stored at different temperatures, was studied. All peaches became woolly during a ripening period of 12 days at 10°C following storage at 2°C, whereas 75% of those stored at –0.6°C developed this disorder. Only 6% of fruit showed symptoms of woolliness after 48 h at 23°C prior to storage. The sugar content, as well as the viscosity of soluble pectin, of peaches stored after the delay period reached a maximum during the 15th day of cold storage, after which it decreased until the end of the ripening period. In peaches stored immediately, however, the maximum sugar content and viscosity was reached during the ripening period. Pectinesterase (PE) activity fluctuated between the different treatments and its possible role in the development of woolliness is not clear. The polygalacturonase (PG) activity of those peaches which became woolly after being stored directly at either temperature was markedly lower over the first 21 days’ storage than peaches which were initially subjected to delay before storage. A sharp increase in PG-activity of the peaches which developed woolliness was observed during the ripening period.

The production of surfactin by Bacillus subtilis grown on peat hydrolysate

Horticultural grade sphagnum peat was subjected to acid hydrolysis under various conditions. The hydrolysis was accomplished with concentrations of sulphuric acid between 0.5 and 2% for either 1 or 2 h at 124°C. Six monosaccharides in the hydrolysate were identified by HPLC analysis. A maximum sugar concentration of 7.7g/l was obtained with glucose accounting for 46% of the total.

Response of eight sugarcane cultivars to glyphosine and glyphosate ripeners

Studies were conducted on eight sugarcane (Saccharum spp. hydrid) cultivars during the 1982–83 (plant crop) and 1983–84 (ratoon crop) growing seasons to determine the effects of glyphosine (Polaris) (N,N-bis (phosphonomethyl) glycine) and glyphosate (Polado) (sodium-N-(phosphonomethyl) glycine) on stalk sucrose content and yield. Difference due to crops (plant vs. ratoon) for sugarcane quality, kilograms of sugar per ton of cane (S/T), sugarcane yield, tons of cane per hectare (TCH), and sugar yield, tons of sugar per hectare (TSH) were significant. Significant differences were found in quality for the ratoon crop and cane and sugar yield in both crops due to ripener treatment. Cultivars in both crops differed significantly in quality and yield. Harvest dates were significantly different for all plant characteristics. Interactions of cultivar by treatment for the plant crop, harvest date by treatment for the ratoon crop, and cultivar by harvest date for both crops for cane quality also were significant. Time from ripener application to achievement of maximum sugar concentration also depended on cultivar. This is important in determining the economic benefits of a ripener treatment. Climatic conditions may also affect the benefits of such applications.

Effect of Low Salt Concentrations on Nitrate Reductase and Peroxidase of Sugar Beet Leaves

Nitrate reductase, peroxidase, nitrate and sugar contents of sugar beet leaves were increased by low NaCl concentrations. The salt was applied in the nutrient solution at concentrations of 2, 4 and 10 mM and determinations were made at 24, 48, 72 and 96 h after salt applications. Nitrate reductase was assayed both in vitro and in vivo. In the latter case maximum activity was attained in the first 24 h for all salt concentrations after which there was a decline until control level was reached. Maximum nitrate content was observed at 48 h. It is suggested that in the first hours the salt stimulated preferentially the flux of nitrate into the inducer nitrate pool. Maximum sugar content occurred in the first 24 h. This may be associated with the increase in nitrate reductase activity as sugars are a source of reducing power for the enzyme and can supply energy and carbon skeletons for the induction process. The salt treatments also stimulated peroxidase, maximum activity being reached at 48 h.

Sugarbeet yield–weather modelling in Iran aimed at forecasting

Sugar content and beet yield data from variety trials as well as sugar content data from commerical farms were analysed to obtain weather-based models which could explain variations of tuber and sugar yield and be used for forecasting purposes. Both sugarbeet yield parameters were found to be related to the sums of thermal deviations from the optimum ranges. Quantitative relationships have been established and the precision of prediction and function of prediction time have been examined and presented. It is shown that most sugarbeet growing areas of Iran are too hot during August and September. Using commercial data, quantitative relationships were established such that using August and September temperatures, the thermal suitability of an area for maximum sugar content could be determined.