Microbial community structure and dynamics in a mixotrophic nitrogen removal process using recycled spent caustic under different loading conditions

A laboratory-scale Bardenpho process was established to investigate the proper nitrogen loading rate (NLR) when modified spent caustic (MSC) is applied as electron donor and alkalinity source for denitrification. MSC injection induced autotrophic nitrogen removal with sulfur as electron donor and heterotrophic denitrification. The nitrogen removal rate (NRR) did not increase proportionally to NLR. Based on the total nitrogen concentration in the effluent observed in the trials with MSC, the NLR in the influent should not exceed 0.15 kg N/m³ d in order to satisfy water quality regulations. Microbial communities in the anoxic reactors were characterized by pyrosequencing of 16S rRNA gene sequences amplified by the polymerase chain reaction of DNA extracted from sludge samples. Microbial diversity was lower as MSC dosage was increased, and the injection of MSC caused an increase in SOB belonging to the genus Thiobacillus which is responsible for denitrification using sulfur.     

长双歧杆菌TTF菌株增强机体免疫活性研究

通过长双岐杆菌TTF活菌、菌体破碎物和发酵上清液3种处理物灌胃正常小鼠和免疫功能低下小鼠试验发现,长双歧杆菌TTF的3种受试物对环磷酰胺（Cy）造成的免疫功能低下小鼠模型（IDMM）3项免疫指标均有显著（P〈0．05）或极显著（P〈0．01）影响,且在本试验选取的3个剂量范围内基本呈量效关系。B．longum TTF的3种受试物对IDMM的非特异性免疫功能的影响普遍大于对小鼠的细胞免疫和体液免疫的影响;对正常小鼠免疫功能影响的水平低于其对IDMM各项免疫指标的影响,且无论活菌、菌体破碎物、发酵上清液均不会改变小鼠自身正常的免疫功能。急性毒性试验表明,B．longum,TTF3种处理物对健康小鼠无急性毒性。就3种处理物来讲,发酵上清液组的效果高于菌体破碎物和活菌。     

Optional tool use: The case of wild bearded capuchins (Sapajus libidinosus) cracking cashew nuts by biting or by using percussors

Tool use in humans can be optional, that is, the same person can use different tools or no tool to achieve a given goal. Strategies to reach the same goal may differ across individuals and cultures and at the intra‐individual level. This is the first experimental study at the intra‐individual level on the optional use of a tool in wild nonhuman primates. We investigated optional tool use by wild bearded capuchins (Sapajus libidinosus) of Fazenda Boa Vista (FBV; Piauí, Brazil). These monkeys habitually succeed in cracking open the mesocarp of dry cashew nuts (Anacardium spp.) by pounding them with stones and/or by biting. We assessed whether availability of a stone and resistance of the nut affected capuchins' choice to pound or to bite the nuts and their rates of success. Sixteen capuchins (1–16 years) received small and large dry cashew nuts by an anvil together with a stone (Stone condition) or without a stone (No‐Stone condition). In the Stone conditions, subjects used it to crack the nut in 89.1% (large nuts) and 90.1% (small nut) of the trials. Nut size significantly affected the number of strikes used to open it. Availability of the stone significantly increased the average percent of success. In the No‐Stone conditions, monkeys searched for and used other percussors to crack the nuts in 54% of trials. In all conditions, age affects percentage of success and number of strikes to reach success. We argue that exclusive use of stones in other sites may be due to the higher abundance of stones at these sites compared with FBV. Since capuchins opened cashews with a tool 1–2 years earlier than they succeed at cracking more resistant palm nuts, we suggest that success at opening cashew nuts with percussors may support the monkeys' persistent efforts to crack palm nuts.     

From discovery to eradication of schistosomiasis in Japan: 1847–1996

Among the areas in Japan where schistesome infections have occurred for many years, three major areas were Katayama District, Kofu Basin and Chikugo River Basin and three minor areas were Numazu District, Tone River Basin and Obitsu River Bank. The presence of the disease had long been recognised in the Katayama Memoir written by Fujii (1847, in the Chinese Classics). The cause of this endemic disease had been studied by many researchers, and finalty a new treamatode, Schistosoma japonicum, was discovered by Katsurada in 1904 [Tokyo Iji Shinski, Vol. 1371, pp. 13–32]. The route of percutaneous infection was proven by Fujinami & Nakamura (1909) [Kyoto Medical Journal, Vol. 6, pp. 224–252] using 17 calves. Miyairi & Suzuki (1913) [Tokyo Iji Shinshi, Vol. 1836, pp. 1961–1965] determined a small snail, Oncomelania nosophora, as being the intermediate best, and clarified the development of the schistosome in the snail. To kill schistosome eggs, human faecal matter (‘night soil’) was stored for 2 weeks or more before using as fertiliser. Control of the parasite used canstic lime and calcium cyanamide to kill eggs, cercariae and Oncomelania snails. Susceptible cows were replaced with horses, which were more resistant to infection as the animal of burden for agriculture. Ditches around the rice fields were comented for destruction of snail habitats. For snail control, sodium pentachlorophenate (NaPCP) was sprayed extensively. Some wetlands were drained and reclaimed and in selected localities, the river bottom was dredged. Such projects were undertaken with government support and aided by community participation. Epidemiological surveys began in 1910, first at Kofu, and infected people were treated with sodium tartar emetic (Stibnal) after 1921. The total number of cases detected in Japan in 1920 was about 8000. This figure was reduced annually down to 438 by 1970. The last human case of new infection found in Japan was at Kofu in 1977. Although snails were cradicated in most areas by 1983, a limited number of uninfected snails remain at Kofu and Obitsu.     

Antihypertensive effect of spent brewer yeast peptide

Numerous studies have investigated dietary approaches to prevent chronic lifestyle-related diseases, including hypertension. Spent brewer’s yeast is the second largest byproduct originated by the brewing industry and it deserves considerable attention because of its high nutritional value, ca. 40% of its dry mass is rich in protein which can be hydrolyzed into biologically active peptides. To upgrade this byproduct, the aim of this study was initially in vitro assessment of biological properties, e.g. ACE inhibition and antioxidant activity, and then, the in vivo effect in short-term oral antihypertensive effect of hydrolyzed yeast fractions on a well characterized model to study hypertension - Spontaneously Hypertensive Rats (SHR). Here, it was demonstrated that the fraction with molecular weight below 3 kDa containing tri and tetra- peptides with hydrophobic amino acid residues – SPQW, PWW and RYW, causes the most noticeable decrease in systolic, diastolic and mean blood pressure of SHR and shows highest antioxidant effect. These properties highlight the potential use of yeast extract as nutraceutical or functional food ingredient for the management and treatment of hypertension with antioxidant effect.     

Strain improvement of the pentose-fermenting yeast Pichia stipitis by genome shuffling

Genome shuffling based on cross mating was used to improve the tolerance of the pentose-fermenting yeast Pichia stipitis towards hardwood spent sulphite liquor (HW SSL). Six UV-induced mutants of P. stipitis were used as the starting strains, and they were subjected to 4 rounds of genome shuffling. After each round, improved strains were selected based on their growth on HW SSL gradient plates. Mutant libraries were established after each round and these improved mutant strains served as the starting pool for the next round of shuffling. Apparent tolerance to HW SSL on the gradient plate increased progressively with each round of shuffling up to 4 rounds. Selected improved mutants were further tested for tolerance to liquid HW SSL. After 4 rounds of shuffling, 4 mutants, two from the third round (designated as GS301 and GS302) and two from the fourth round (designated as GS401 and GS402), were selected that could grow in 80% (v/v) HW SSL. GS301 and GS302 grew also in 85% (v/v) HW SSL. GS301 was viable in 90% (v/v) HW SSL, although no increase in cell number was seen. The P. stipitis wild type strain (WT) could not grow on HW SSL unless it was diluted to 65% (v/v) or lower. Genome-shuffled strains with improved tolerance to HW SSL retained their fermentation ability. Fermentation performance of GS301 and GS302, the 2 strains that exhibited the best tolerance to liquid HW SSL, was assessed in defined media and in HW SSL. Both strains utilized 4% (w/v) of xylose or glucose more efficiently and produced more ethanol than the WT. They also utilized 4% (w/v) of mannose or galactose and produced ethanol to the same extent as the WT. GS301 and GS302 were able to produce low levels of ethanol in undiluted HW SSL.     

Evaluation of three composting systems for the management of spent coffee grounds

This study was conducted to evaluate the optimum composting approach for the management of spent coffee grounds from the restaurant and ready-to-serve coffee industry. Three composting systems were assessed, including in-vessel composting, vermicomposting bins, and aerated static pile bin composting, over study periods ranging from 47 to 98 days. Total carbon content was reduced by 5-7% in the spent coffee ground treatments across the three composting systems. Nitrogen and other mineral nutrient contents were conserved or enhanced from the initial to the final composts in all the composting systems assessed. Earthworm growth and survival (15-80%) was reduced in all the treatments but mortality rates were lower in coffee treatments with cardboard additions. A decline in earthworm mortality with cardboard additions was the result of reduced exposure to organic compounds and chemicals released through the decomposition of spent coffee grounds.     

Production of spent mushroom substrate hydrolysates useful for cultivation of Lactococcus lactis by dilute sulfuric acid, cellulase and xylanase treatment

Spent mushroom substrate (SMS) was treated with dilute sulfuric acid followed by cellulase and xylanase treatment to produce hydrolysates that could be used as the basis for media for the production of value added products. A L9 (3⁴) orthogonal experiment was performed to optimize the acid treatment process. Pretreatment with 6% (w/w) dilute sulfuric acid at 120 °C for 120 min provided the highest reducing sugar yield of 267.57 g/kg SMS. No furfural was detected in the hydrolysates. Exposure to 20 PFU of cellulase and 200 XU of xylanase per gram of pretreated SMS at 40 °C resulted in the release of 79.85 g/kg or reducing sugars per kg acid pretreated SMS. The dilute sulfuric acid could be recycled to process fresh SMS four times. SMS hydrolysates neutralized with ammonium hydroxide, sodium hydroxide, or calcium hydroxide could be used as the carbon source for cultivation of Lactococcus lactis subsp. lactis W28 and a cell density of 2.9 × 10¹¹ CFU/mL could be obtained. The results provide a foundation for the development of value-added products based on SMS.     

Nitrate removal with bacterial cells attached to quartz sand and zeolite from salty wastewaters

A mixed bacterial culture was acclimated to the removal of high nitrate-N concentrations (100–750 mg NO₃ ⁻-N L⁻¹) from salty wastewaters. The experiments were carried out under anoxic conditions in the presence of 0.5, 1.5 and 3% (w/v) NaCl at different temperatures. The acclimated mixed bacterial culture was attached to quartz sand and zeolite. Denitrification was monitored in a continuous-flow bioreactor at different hydraulic retention times (HRT). Nitrate removal with cells attached to quartz sand and zeolite was completed at HRT of 167 h and 25 h respectively. Then brine denitrification with bacterial cells attached to zeolite was monitored for 85 days. Under the increased nitrate loading rate, nitrate removal was above 90%. Furthermore, during denitrification, not more than 0.5 mg NO₂ ⁻-N L⁻¹ could be produced. It can be concluded that nitrate removal with the cells attached to zeolite is economically and operationally a promising solution to denitrification of brine wastewaters.     

A new method of autotrophic denitrification with spent sulfidic caustic as substrate and alkalinity source

A new method based on sulfide utilizing autotrophic denitrification was adopted to remove nitrate from wastewater and to reuse spent sulfidic caustic containing high sulfide and alkalinity levels. The experiments were performed using a bench-scale upflow anoxic hybrid growth reactor (UAHGR) and an upflow anoxic suspended growth reactor (UASGR) to characterize the stoichiometric relationship between sulfur and nitrate in the process as well as the performance of the reactors. The level of nitrate removal from the UAHGR and UASGR were maintained at over 90% at a nitrate loading rate ranging from 0.15∼0.40 kgNO₃ ⁻/m³·d and no significant nitrite accumulation was observed in either reactor. Although the influent pH values were higher than the optimum range of autotrophic denitrification at 8.7∼10.1, the effluent pH was stable at 7.2∼7.9 due to the production of hydrogen ions during operation. The stoichiometric ratio of sulfate production to nitrate removal was 1.5∼2.1 mgSO₄ ²⁻/mgNO₃ ⁻ in both reactors. A comparison of the reactor performance revealed that the chemical parameters of the UAHGR operation corresponded to a plug flow like type reactor while the chemical parameters of the UASGR operation corresponded to a completely stirred tank reactor like type reactor. UAHGR did not require sludge recycling due to the packed media while UASGR required 300∼700% sludge recycling. Therefore, spent sulfidic caustic could be used in the sulfur utilizing autotrophic denitrification processes as substrate and alkalinity sources.