The cation-dependent galactose-specific flocculation activity of the Schizosaccharomyces pombe null mutant of lkh1⁺, the gene encoding LAMMER kinase homolog, has previously been reported by our group. Here, we show that disruption of prk1⁺, another flocculation associated regulatory kinase encoding gene, also resulted in cation-dependent galactose-specific flocculation. Deletion of prk1 increased the flocculation phenotype of the lkh1⁺ null mutant and its overexpression reversed the flocculation of cells caused by lkh1 deletion. Transcript levels of prk1⁺ were also decreased by lkh1⁺ deletion. Cumulatively, these results indicate that Lkh1 is one of the negative regulators acting upstream of Prk1, regulating non-sexual flocculation in fission yeast.
Flocculation* ; Phenotype ; Phosphotransferases* ; Schizosaccharomyces*

PURPOSE: To evaluate the efficacy of a modified small bowel follow-through (SBFT) and to optimize this technique. MATERIALS AND METHODS: Ninety-nine subjects without small bowel pathology underwent modified SBFT using oral administration of methylcellulose after taking 100ml of 120% or 100, 150, or 200ml of 70% barium. Thirty-three and 39 normal subjects undergoing enteroclysis or conventional SBFT, respectively, were also evaluated for comparison of image qualities and transit time. RESULTS: Enteroclysis was the most successful ofthree types of small bowel examination for obtaining the best quality of bowel transradiency and distension. Modified SBFT was, however much superior to the conventional series for obtaining good bowel transradiency and rapid transity time (mean, 37-49 minutes). The use of 150ml of 70% barium was better than the other three modified techniques in achieving good bowel transradiency, rapid transit time, and less flocculation. CONCLUSION: Our modified SBFT is a simple and safe method for easily improving bowel transradiency and transit time.
Administration, Oral ; Barium ; Flocculation ; Methylcellulose* ; Pathology

Microalgae have been identified as promising candidates for biorefinery of value-added molecules. The valuable products from microalgae include polyunsaturated fatty acids and pigments, clean and sustainable energy (e.g. biodiesel). Nevertheless, high cost for microalgae biomass harvesting has restricted the industrial application of microalgae. Flocculation, compared with other microalgae harvesting methods, has distinguished itself as a promising method with low cost and easy operation. Here, we reviewed the methods of microalgae harvesting using flocculation, including chemical flocculation, physical flocculation and biological flocculation, and the progress and prospect in bio-flocculation are especially focused. Harvesting microalgae via bio-flocculation, especially using bio-flocculant and microalgal strains that is self-flocculated, is one of the eco-friendly, cost-effective and efficient microalgae harvesting methods.
Biofuels ; Biomass ; Flocculation ; Microalgae ; growth & development

Intense utilization and mining of fossil fuels for energy production have resulted in environmental pollution and climate change. Compared to fossil fuels, microalgae is considered as a promising candidate for biodiesel production due to its fast growth rate, high lipid content and no occupying arable land. However, monocultural microalgae bear high cost of harvesting, and are prone to contamination, making them incompetent compared with traditional renewable energy sources. Co-culture system induces self-flocculation, which may reduce the cost of microalgae harvesting and the possibility of contamination. In addition, the productivity of lipid and high-value by-products are higher in co-culture system. Therefore, co-culture system represents an economic, energy saving, and efficient technology. This review aims to highlight the advances in the co-culture system, including the mechanisms of interactions between microalgae and other microorganisms, the factors affecting the lipid production of co-culture, and the potential applications of co-culture system. Finally, the prospects and challenges to algal co-culture systems were also discussed.
Biofuels ; Biomass ; Coculture Techniques ; Flocculation ; Microalgae

OBJECTIVETo isolate the bioflocculant-producing bacteria from activated sludge and investigate the flocculating characteristics of the newly isolated bioflocculant.

METHODSBacteria were screened from activated sludge samples to isolate bioflocculant-producing bacteria. Flocculating activity was used as a measure of the flocculating capability of the bioflocculant.

RESULTSA novel bioflocculant-producing bacterium was isolated, which was identified to belong to genus Aeromonas and named as Aeromonas sp. N11. Flocculating activity increased in the presence of K+, Na+, or Ca2+. The highest flocculating activities for kaolin suspension were obtained in acidic pH ranges, and optimum pHs for it were 3.0, 4.0, and 5.0 with 1 mmol/L K+, Ca+, and Na+ present, respectively. The highest flocculating activities for soil suspension were observed at pH 8.0. The bioflocculant had a good flocculating activity and could achieve a flocculating activity of 92.4% for kaolin suspension at a dosage of only 1 mgxL(-1), and its activity in kaolin suspension was decreased by only 9.2% after heating at 100 degrees C for 60 min.

CONCLUSIONThe bioflocculant produced by Aeromonas sp. N11 has strong flocculating activity and high stability, which affords high possibility of its practical use.

Propionic acid, a major inhibitor to yeast cells, was accumulated during continuous ethanol fermentation from corn meal hydrolysate by the flocculating yeast under stillage backset conditions. Based on its inhibition mechanism in yeast cells, strategies were developed for alleviating this effect. Firstly, high temperature processes such as medium sterilization generated more propionic acid, which should be avoided. Propionic acid was reduced significantly during ethanol fermentation without medium sterilization, and concentrations of biomass and ethanol increased by 59.3% and 7.4%, respectively. Secondly, the running time of stillage backset should be controlled so that propionic acid accumulated would be lower than its half inhibition concentration IC50 (40 mmol/L). Finally, because low pH augmented propionic acid inhibition in yeast cells, a higher pH of 5.5 was validated to be suitable for ethanol fermentation under the stillage backset condition.
Biomass ; Ethanol ; metabolism ; Fermentation ; Flocculation ; Propionates ; chemistry ; Yeasts ; metabolism

PURPOSE: To compare modified small bowel follow-through (SBFT) using methylcellulose after the administrationof barium suspension with a conventional series. MATERIALS AND METHODS: In order to evaluate small bowelpathology, modified SBFT was performed in 155 patients during a 15 month period. All patients received 600mL ofmethylcellulose ; 98 had taken 250mL of 40% wt/vol barium suspension and 57 had taken 150mL of 70% barium. For thegroup of 98, the barium suspension was prepared by mixing barium powder with water (n=46) or with methylcellulosein(n=52). For comparison with a modified series, 49 patients who underwent conventional SBFT using 500mL of 40%wt/vol barium were lso included. Image quality was rated by three radiologists as "poor", "fair", "good", or"excellent". We analyzed the relationship between image quality, transit time and small bowel pathology;the sensitivity and specificity of each technique was also determined. RESULT: Among the four techniques, modifiedSBFT with 250mL of 40% wt/vol barium suspension, prepared by mixing barium powder with methylcellulose, showed thebest image quality ["excellent" result in 33 of the 52 patients (63%)] and shortest transit time to the cecum. Thehigh image quality of this technique was not affected by the presence of small bowel pathology;its use resulted inthe lowest incidence and slowest development of flocculation. The sensitivity (91-95%) of the three modified SBFTprocedures was superior to that of a conventional series(76%), but there was no difference in specificity. CONCLUSION: Modified SBFT using methylcellulose after administering barium suspension with barium powder as amixing agent is a simple technique. Its use easily improves the image quality and diagnostic accuracy of peroralSBFT.
Barium* ; Cecum ; Flocculation ; Humans ; Incidence ; Methylcellulose* ; Sensitivity and Specificity ; Water

A continuous ethanol fermentation system composed of three-stage tanks in series coupled with two sedimentation tanks was established. A self-flocculating yeast strain developed by protoplast fusion from Saccharomyces cerevisiae and Schizosaccharomyces pombe was applied. Two-stage enzymatic hydrolysate of corn powder containing 220g/L of reducing sugar, supplemented with 1.5g/L (NH4)2HPO4 and 2.5g/L KH2PO4, was used as the ethanol fermentation substrate and fed into the first fermentor at the dilution rate of 0.057h(-1). The yeast flocs separated by sedimentation were recycled into the first fermentor as two different models: activation-recycle and direct recycle. The quasi-steady states were obtained for both operation models after the fermentation systems experienced short periods of transitions. Activation process helped enhance the performance of ethanol fermentation at the high dilution rates. The broth containing more than 101g/L ethanol, 3.2g/L residual reducing sugar and 7.7g/L residual total sugar was produced. The ethanol productivity was calculated to be 5.77g/(L x h), which increased by more than 70% compared with that achieved in the same tank in series system without recycling of yeast cells.
Biomass ; Ethanol ; metabolism ; Fermentation ; Flocculation ; Saccharomyces cerevisiae ; metabolism

A continuous ethanol fermentation system composed of four-stage tank fermentors in series and with a total working volume of 4000 mL was established. The first fermentor was designated as the seed fermentor and the others for ethanol fermentation. A self-flocculating yeast strain developed by protoplast fusion of Saccharomyces cerevisiae and Schizosaccharomyces pombe was applied. Two-stage corn powder enzymatic hydrolyzate containing reducing sugar 100 g/L, together with 2.0 g/L (NH4)2HPO4 and KH2PO4, was used as yeast seed culture medium and fed into the seed fermentor at the dilution rate of 0.017h (-1). Meanwhile, the hydrolyzate containing reducing sugar 220 g/L, added with 1.5 g/L (NH4)2HPO4 and 2.5 g/L KH2PO4, was used as ethanol fermentation substrate and fed into the second fermentor at the dilution rates of 0.017, 0.025, 0.033, 0.040 and 0.050 h(-1) (based on the total working volume of the three fermentors), respectively. The chemostat states on which all of the monitoring parameters, including residual sugar, ethanol and yeast cell biomass concentrations, were maintained relatively constant were observed for seed cultivation and ethanol fermentations when the fermentation system was operated at the dilution rates of 0.017, 0.025, 0.033 and 0.050 h(-1). Yeast cells were observed being partly immobilized because significant yeast cell biomass concentration differences between the broth out of and inside the fermentors were detected. Moreover, the oscillations of residual sugar, ethanol and yeast cell biomass concentrations were observed when the fermentation system was operated at the dilution rate of 0.040 h(-1). The broth containing more than 12% (V/V) ethanol and less than 0.11% (W/V) residual reducing sugar and 0.35% (W/V) residual total sugar was produced when the dilution rate was controlled at no more than 0.033 h(-1). The ethanol productivity was calculated to be 3.32(g x L(-1) x h(-1)) for the dilution rate of 0.033 h(-1), which increased nearly 100% compared with that for conventional ethanol fermentation technologies using freely suspended yeast cells.
Bioreactors ; microbiology ; Carbohydrates ; Ethanol ; metabolism ; Fermentation ; Flocculation ; Saccharomyces cerevisiae ; metabolism ; Schizosaccharomyces ; metabolism ; Zea mays ; metabolism

A study on flocculation control based on fractal theory was carried out. Optimization test of chemical coagulant dosage confirmed that the fractal dimension could reflect the flocculation degree and settling characteristics of aggregates and the good correlation with the turbidity of settled effluent. So that the fractal dimension can be used as the major parameter for flocculation system control and achieve self-acting adjustment of chemical coagulant dosage. The fractal dimension flocculation control system was used for further study carried out on the effects of various flocculation parameters, among which are the dependency relationship among aggregates fractal dimension, chemical coagulant dosage, and turbidity of settled effluent under the conditions of variable water quality and quantity. And basic experimental data were obtained for establishing the chemical coagulant dosage control model mainly based on aggregates fractal dimension.
Aluminum Hydroxide ; chemistry ; Flocculation ; Fractals ; Fresh Water ; chemistry ; Pilot Projects ; Water Purification ; methods