Evaluation of three cultivars of sweet sorghum as feedstocks for ethanol production in the Southeast United States.

Sweet sorghum has become a promising alternative feedstock for biofuel production because it can be grown under reduced inputs, responds to stress more efficiently than traditional crops, and has large biomass production potential. A three-year field study was conducted to evaluate three cultivars of sweet sorghum as bioenergy crops in the Southeast United States (Fort Valley, Georgia): Dale, M81 E and Theis. Parameters evaluated were: plant density, stalk height, and diameter, number of nodes, biomass yield, juice yield, °Bx, sugar production, and theoretical ethanol yields. Yields were measured at 85, 99, and 113 days after planting. Plant fresh weight was the highest for Theis (1096 g) and the lowest for Dale (896 g). M81 E reported the highest stalk dry weight (27 Mg ha-1) and Theis reported the lowest (21 Mg ha-1). Theis ranked the highest °Bx (14.9), whereas M81 E was the lowest (13.2). Juice yield was the greatest for M81 E (10915 L ha-1) and the lowest for Dale (6724 L ha-1). Theoretical conservative sugar yield was the greatest for Theis (13 Mg ha-1) and the lowest for Dale (9 Mg ha-1). Theoretical ethanol yield was the greatest for Theis (7619 L ha-1) and the lowest for Dale (5077 L ha-1).

Simultaneous saccharification and fermentation of Kanlow switchgrass by thermotolerant Kluyveromyces marxianus IMB3: the effect of enzyme loading, temperature and higher solid loadings.

Switchgrass (Panicum virgatum) was subjected to hydrothermolysis pretreatment and then used to study the effect of enzyme loading and temperature in a simultaneous saccharification and fermentation (SSF) with the thermotolerant yeast strain Kluyveromyces marxianus IMB3 at 8% solid loading. Various loadings of Accellerase 1500 between 0.1 and 1.1 mL g(-1) glucan were tested in SSF at 45 °C (activity of enzyme was 82.2 FPU mL(-1)). The optimum enzyme loading was 0.7 mL g(-1) glucan based on the six different enzyme loadings tested. SSFs were performed at 37, 41 and 45 °C with an enzyme loading of 0.7 mL g(-1) glucan. The highest ethanol concentration of 22.5 g L(-1) was obtained after 168 h with SSF at 45 °C, which was equivalent to 86% yield. Four different batch and fed-batch strategies were evaluated using a total solid loading of 12% (dry basis). About 32 g L(-1) ethanol was produced with the four strategies, which was equivalent to 82% yield.

Ethanol production from syngas by Clostridium strain P11 using corn steep liquor as a nutrient replacement to yeast extract.

The feasibility of replacing yeast extract (YE) by corn steep liquor (CSL), a low cost nutrient source, for syngas fermentation to produce ethanol using Clostridium strain P11 was investigated. About 32% more ethanol (1.7 g L(-1)) was produced with 20 g L(-1) CSL media in 250-mL bottle fermentations compared to media with 1 g L(-1) YE after 360 h. Maximum ethanol concentrations after 360 h of fermentation in a 7.5-L fermentor with 10 and 20 g L(-1) CSL media were 8.6 and 9.6 g L(-1), respectively, which represent 57% and 60% of the theoretical ethanol yields from CO. Only about 6.1 g L(-1) of ethanol was obtained in the medium with 1 g L(-1) YE after 360 h, which represents 53% of the theoretical ethanol yield from CO. The use of CSL also enhanced butanol production by sevenfold compared to YE in bottle fermentations. These results demonstrate that CSL can replace YE as the primary medium component and significantly enhance ethanol production by Clostridium strain P11.

Simultaneous saccharification and fermentation of Kanlow switchgrass pretreated by hydrothermolysis using Kluyveromyces marxianus IMB4.

A thermotolerant yeast strain named Kluyveromyces marxianus IMB4 was used in a simultaneous saccharification and fermentation (SSF) process using Kanlow switchgrass as a feedstock. Switchgrass was pretreated using hydrothermolysis at 200 degrees C for 10 min. After pretreatment, insoluble solids were separated from the liquid prehydrolyzate by filtration and washed with deionized water to remove soluble sugars and inhibitors. Insoluble solids were then hydrolyzed using a commercial cellulase preparation and the released glucose was fermented to ethanol by K. marxianus IMB4 in an SSF process. SSF temperature was 37, 41, or 45 degrees C and pH was 4.8 or 5.5. SSF was conducted for 7 days. Results were compared with a control of Saccharomyces cerevisiae D(5)A at 37 degrees C and pH 4.8. Fermentation by IMB4 at 45 and 41 degrees C ceased after 3 and 4 days, respectively, when a pH 4.8 citrate buffer was used. Fermentation continued for all 7 days using IMB4 at 37 degrees C and the control. When pH 5.5 citrate buffer was used, fermentation ceased after 96 h using IMB4 at 45 degrees C, and ethanol yield was greater than when pH 4.8 citrate buffer was used (78% theoretical). Ethanol yield using IMB4 at 45 degrees C, pH 5.5 was greater than the control after 48, 72, and 96 h (P < 0.05).

The effects of fructo-oligosaccharides in combination with soy protein on bone in osteopenic ovariectomized rats.

OBJECTIVE: The intestinal microflora is important in rendering soy isoflavones bioavailable by facilitating their conversion to equol. Hence, substances that can modulate the intestinal microflora could affect the bioavailability of isoflavones. In this study, we examined the effects of fructo-oligosaccharides (FOS), a prebiotic, on enhancing the effects of soy isoflavones on bone in ovariectomized osteopenic female rats. DESIGN: Sixty-three 9-month-old female Sprague-Dawley rats were either sham-operated (Sham; one group) or ovariectomized (Ovx; four groups) and were fed a control diet for 3 months to induce bone loss. After bone loss was confirmed via dual-energy x-ray absorptiometry, rats were placed on dietary treatment for 4 months. The Sham and one Ovx group received a control diet, and the remaining Ovx groups received either a soy protein-based diet (Soy), a FOS-supplemented diet (FOS), or a soy protein-based and FOS-supplemented diet (Soy+FOS). Before the termination of the study, whole-body bone mineral density (BMD) and bone mineral content (BMC) were assessed under anesthesia. Immediately after euthanasia, bone specimens were collected for the assessments of BMD, BMC, and biomechanical and microarchitectural properties. RESULTS: Whole-body BMD values were significantly higher in FOS and Soy+FOS groups compared with Ovx controls. The tibial BMC increased by 10%, 6%, and 4% in Soy, FOS, and Soy+FOS groups, respectively, compared to the Ovx control group. FOS and FOS+Soy treatments had the most pronounced effects in enhancing lumbar BMC and BMD. The FOS+Soy combination effectively improved tibial microarchitectural properties by enhancing trabecular number and lowering trabecular separation compared with Ovx controls. The effects of dietary treatments on lumbar microarchitectural properties were minimal and biomechanical properties of the femur were not affected by any of the dietary treatments. CONCLUSION: Our findings suggest that, although incorporation of either soy or FOS in the diet of Ovx rats can improve BMD of the whole body, tibiae, and lumbar vertebrae, their combination had no any additive effects. However, in terms of microarchitecture, the combination of soy and FOS had a greater effect in reversing the loss of certain microarchitectural parameters such as tibial trabecular number, separation, and thickness.

Physical quality and carotene content of solar-dried green leafy and yellow succulent vegetables.

The effects of vegetable type, vegetable dimensions, and solar drier load on dehydration rate; and texture, color, water activity, and carotene content of solar-dried carrots, sweet potatoes, and collard greens were studied. Mean dehydration rates (moisture loss,%/hr) for solar dried loads of 430 g/m2 and 715 g/m2 were 3.3 +/- 0.30% and 3.8 +/- 0.20% for carrots and sweet potatoes, respectively. Loads of 360 g/m2 and 465 g/m2 of collard greens had dehydration rates of 6.3 +/- 0.10% moisture loss per hr. The results showed that vegetable type accounted for significant differences (p < 0.01) in dehydration rate, and beta-carotene content. Vegetable dimensions affected (p < 0.05) water activity. Solar drier load affected water activity (p < 0.01), and hue angle (p < 0.05). Beta-carotene contents (dry basis) of dehydrated carrot, sweet potato, and collard treatments were 10.9-17.4%, 7.6-9.8%, and 11.9-21.5%, respectively. Among the carrot treatments, the 5-mm thick slices packed at a load of 715 g/m2 contained the highest beta-carotene (17.4%, dry basis) and vitamin A activity (362 IU/g, dry basis), and good physical properties. For collard greens, the 2-cm and 3-cm wide strips packed at 360 g/m2 loads had the best combinations of high beta-carotene (21.5% and 17.2%, dry basis, respectively), vitamin A activity (357.2 and 293.1 IU/g, dry basis, respectively), and optimal color, texture, and water activity. Beta-carotene losses due to solar dehydration were 48.9-67.5%, 4.0-5.8%, and 1.9-19.8% (dry basis) in carrots, sweet potato and collard greens, respectively.

Evaluation of the tensile strengths of four monofilament absorbable suture materials after immersion in canine urine with or without bacteria.

OBJECTIVE: To evaluate the tensile strength, elongation, and degradation of 4 monofilament absorbable suture materials that undergo degradation by hydrolysis in specimens of canine urine with various physical characteristics. SAMPLE POPULATION: 4 monofilament absorbable sutures (polydioxanone, poliglecaprone 25, polyglyconate, and glycomer 631). PROCEDURE: Voided urine was collected from 6 healthy dogs, pooled, filter-sterilized, and prepared to provide 5 media: sterile neutral (pH, 7.0), sterile acidic (pH, 6.2), sterile basic (pH, 8.8), Escherichia coli-inoculated, and Proteus mirabilis-inoculated urine. Ten strands of each suture material were immersed in each of the media for 0 to 28 days. Tensile strength and elongation of each suture material were evaluated by use of a texture analyzer on days 0, 1, 3, 7, 10, 14, 21, and 28. RESULTS: Reduction in tensile strength was detected for all materials in all urine specimens over time. Polyglyconate and polydioxanone had superior tensile strengths in sterile neutral and E. coli-inoculated urine, and polydioxanone retained the greatest tensile strength throughout the study period. All suture materials disintegrated before day 7 in P. mirabilis-inoculated urine. CONCLUSIONS AND CLINICAL RELEVANCE: Polydioxanone, polyglyconate, and glycomer 631 may be acceptable for urinary bladder closure in the presence of sterile neutral and E. coli-contaminated urine. Tensile strength of poliglecaprone 25 in urine may be unacceptable by the critical healing time for bladder tissue (14 to 21 days). During bladder surgery, exposure of suture material that degrades via hydrolysis to urine containing Proteus spp should be minimized.