The treatment of oily wastewater by thermo-responsive calcium alginate capsules immobilized Pseudomonas aeruginosa.

A microfluidic strategy of smart calcium alginate (CA) capsules is presented to immobilize Pseudomonas aeruginosa to treat oil slicks effectively. The capsule wall is embedded with poly (N-isopropyl acrylamide) sub-microspheres as thermo-responsive switches. CA capsules, with a diameter of 3.26 mm and a thin wall thickness about 12.8 µm, have satisfying monodispersity, cavity structure, and dense surface structures. The capsules possess excellent encapsulation of bacteria, which are fixed in a restricted space and become more aggregated. It overcomes the disadvantages of a long fermentation production cycle, easy loss of bacteria, and susceptibility to shear effect. The smart CA capsules immobilized with bacteria treat model wastewater containing soybean oil or diesel and display favorable fermentation ability. The capsules can effectively treat oil slicks with high concentration, and it is an economical way for processing oily wastewater. PRACTITIONER POINTS: A thermo-responsive calcium alginate capsule was prepared by microfluidic strategy. Pseudomonas aeruginosa is environmentally friendly in treating oil slicks. The capsules, immobilized bacteria, treat oil slicks effectively. This study provides an economical way for processing different oily water.

[Effects of balanced fertilization on growth and fruit quality of 'Huang-guan' pear on desert area.] / å¹³è¡¡æ–½è‚¥å¯¹è’æ¼ åŒºé»„å† æ¢¨ç”Ÿé•¿ä¸Žå“è´¨çš„å½±å“.

A field experiment was carried out to study the effects of balanced fertilization on growth and development, yield, fruit quality and mineral content in 'Huang-guan' pear to provide a theoretical basis for the reasonable level of fertilization in pear orchards. Four treatments were arranged with 12-year old 'Huang-guan' pear trees from the same orchard: conventional fertilization (CK), low levels of N, P2O5 and high level of S (T1), medium levels of N, P2O5 and S (T2), high levels of N, P2O5 and low level of S (T3). The results showed that different treatments had little effect on the growth and development of current-year branch and leaves in the first year. However, in the se-cond year, T1 treatment promoted the length and diameter of current-year branch by 16.2% and 11.4%, respectively. Continuous fertilization could increase the leaf mineral contents in different degrees. The contents of Cu, Fe, and Zn in leaves under T1 treatment, Mg and B in leaves under T2 treatment, and P and Mn in leaves under T3 treatment were highest. Different fertilization levels had no significant effect on yield but on fruit quality. The contents of soluble sugars and vitamin C (Vc) were significantly increased by T2 treatment, which was 4.2% and 7.1% higher than those in CK. However, T1 significantly decreased contents of total soluble solid, soluble sugars and Vc, while highest organic acid content presented in T3. Fruit Fe content was positively correlated with soluble sugar content and fruit shape index, but was negatively correlated with single fruit mass, organic acids and Vc. Fruit P content was positively correlated with fruit shape index and firmness, but was negatively correlated with contents of soluble sugars, organic acids and Vc. Accordingly, T2 could improve fruit quality and maintain the productivity, and thus should be the suitable fertilization strategy for the 'Huang-guan' pear management in desert area.

[Response of distribution pattern and physiological characteristics of apple roots grown in the dry area of eastern Gansu to ground mulching]. / é™‡ä¸œæ—±å¡¬è‹¹æžœæ ¹ç³»åˆ†å¸ƒè§„å¾‹åŠç”Ÿç†ç‰¹æ€§å¯¹åœ°è¡¨è¦†ç›–çš„å“åº”.

The objective of the experiment is to ascertain the effects of different mulching materials on the distribution and physiological activity of apple roots as well as the soil physicochemical pro-perties in the rain-fed Longdong arid areas. With fourteen years old apple trees as test material, the different classes of roots were collected by using soil profile method and stratified sampling in soil profile to investigate the spatial distribution, root biomass, root length and surface area. The activity of root and antioxidant enzymes and some antioxidant indexes were measured. Soil bulk density and soil porosity in different soil layers were determined. The results indicated that ground covering treatment increased the soil moisture, porosity and organic matter content, and the amplification were 2.7%-11.6%, 3.2%-27.7%, 5.1%-36.0%, respectively compared with the control. The soil bulk density was reduced by 88.7%-96.4%. The roots of CK distributed mainly in soil layer of 0-60 cm in depth, 30-120 cm away from the trunk. However, with straw and plastic mulching the roots distributed mainly in the layer of 0-100 cm in depth, 0-150 cm and 0-60 cm away from the trunk, respectively, mostly concentrated in the 20-40 cm layer close to the ground. Plastic mul-ching made a narrower horizontal root distribution than CK and the total fine root amount was 96.4% of that of CK, and that in 0-60 cm layer accounted for 51.6% of the total fine root amount. More-over, the mulching resulted in a higher activity of root and antioxidant enzymes in 0-80 cm layer. The root activity with straw mulching was 111.3%-136.7% as much as the control. For sake of the efficacy on improving root distribution and physiological activity, the straw mulching was suggested as a better way for soil management in apple orchard in dry area of eastern Gansu.

Antibacterial activity of the lipopetides produced by Bacillus amyloliquefaciens M1 against multidrug-resistant Vibrio spp. isolated from diseased marine animals.

In this work, the antibacterial activity of the lipopeptides produced by Bacillus amyloliquefaciens M1 was examined against multidrug-resistant Vibrio spp. and Shewanella aquimarina isolated from diseased marine animals. A new and cheap medium which contained 1.0 % soybean powder, 1.5 % wheat flour, pH 7.0 was developed. A crude surfactant concentration of 0.28 mg/ml was obtained after 18 h of 10-l fermentation and diameter of the clear zone on the plate seeded with Vibrio anguillarum was 34 mm. A preliminary characterization suggested that the lipopeptide N3 produced by B. amyloliquefaciens M1 was the main product and contained the surfactin isoforms with amino acids (GLLVDLL) and hydroxy fatty acids (of 12-15 carbons in length). The evaluation of the antibacterial activity of the lipopeptide N3 was carried out against S. aquimarina and nine species of Vibrio spp.. It was found that all the Vibrio spp. and S. aquimarina showed resistance to several different antibiotics, suggesting that they were the multidrug resistance. It was also indicated that all the Vibrio spp. strains and S. aquimarina were sensitive to the surfactin N3, in particular V. anguillarum. The results demonstrated that the lipopeptides produced by B. amyloliquefaciens M1 had a broad spectrum of action, including antibacterial activity against the pathogenic Vibrio spp. with multidrug-resistant profiles. After the treatment with the lipopeptide N3, the cell membrane of V. anguillarum was damaged, and the whole cells of the bacterium were disrupted.

Antifungal activity of the lipopeptides produced by Bacillus amyloliquefaciens anti-CA against Candida albicans isolated from clinic.

The bacterium Bacillus amyloliquefaciens anti-CA isolated from mangrove system was found to be able to actively kill Candida albicans isolated from clinic. The bacterial strain anti-CA could produce high level of bioactive substance, amylase and protease in the cheap medium containing 2.0 % soybean meal, 2.0 % wheat flour, pH 6.5 within 26 h. After purification, the main bioactive substance was confirmed to be a cyclic lipopeptide containing a heptapeptide, L-Asp→L-Leu→L-Leu→L-Val→L-Val→L-Glu→L-Leu and a 3-OH fatty acid (15 carbons). In addition to C. albicans, the purified lipopeptide can also kill many yeast strains including Metschnikowia bicuspidata, Candida tropicalis, Yarrowia lipolytica and Saccharomyces cerevisiae. After treated by the purified lipopeptide, both the whole cells and protoplasts of C. albicans were destroyed.

Trehalose accumulation from cassava starch and release by a highly thermosensitive and permeable mutant of Saccharomycopsis fibuligera.

Highly thermosensitive and permeable mutants are the mutants from which intracellular contents can be released when they are incubated both in low osmolarity water and at non-permissive temperature (usually 37°C). After mutagenesis by using nitrosoguanidine, a highly thermosensitive and permeable mutant named A11-b was obtained from Saccharomycopsis fibuligera A11-12, a trehalose overproducer in which the acid protease gene has been disrupted. Of the total trehalose, 73.8% was released from the mutant cells suspended in distilled water after they had been treated at 37°C overnight. However, only 10.0% of the total trehalose was released from the cells of S. fibuligera A11-12 treated under the same conditions. The cell volume of the mutant cells suspended in distilled water and treated at 37°C overnight was much bigger than that of S. fibuligera A11-12 treated under the same conditions. The cell growth and trehalose accumulation of the mutant were almost the same as those of S. fibuligera A11-12 during the cultivation at the flask level and in a 5-l fermentor. Both could accumulate around 28.0% (w/w) trehalose from cassava starch. After purification, the trehalose crystal from the aqueous extract of the mutant was obtained.