OBJECTIVETo study the characteristics of a bioflocculant named MBF7 produced by Penicillum strain HHE-P7 and the effects of cultivation conditions on bioflocculant production.

METHODSThe chemical group in the bioflocculant molecules was shown by Fourier transform infrared (FTIR) spectra, and the average molecular weight of MBF7 was estimated by gel permeation chromatography. The effects of medium components on bioflocculant production and flocculating activity were studied.

RESULTSPhospho-, amino-, hydroxyl, and carboxyl groups were the major fractions of MBF7, and the molecule weight was about 3.0x10(5) Da. In addition, the carbon and nitrogen sources favorable for the bioflocculant production were glucose and yeast extract respectively. When the initial pH of the medium was adjusted to 5.0, high flocculant efficiency could be achieved.

CONCLUSIONThe bioflocculant MBF7 is a new macromolecule with high flocculating efficiency for Kaolin suspension, and could be produced under appropriate culture conditions.

Culture Media ; Hydrogen-Ion Concentration ; Penicillium ; metabolism

We investigated the effect of adding intermediate metabolites on cell growth and succinate production. The yield of succinic acid achieved to the highest when 0.5 g/L phosphoenolpyruvic acid (PEP) was added. According to the metabolic network of Actinobaccilus succinogenes NJ113, the metabolic flux was calculated by metabolic flux analysis. The ratio of hexose monophosphate pathway to glycolytic pathway increased from 39.4:60.3 to 76.8:22.6 after adding 0.5 g/L PEP, thus the reducing power was better balanced. The flux of PEP to oxaloacetate was 23.8% higher, which made the succinic acid flux improve from 99.8 mmol/(g DCW x h) to 124.4 mmol/(g DCW x h) and the flux of acetic acid and formic acid decreased by 22.9% and 15.4%, respectively. The key enzyme activity analysis showed that the specific activity of PEP carboxykinase reached to 1910 U/mg with 0.5 g/L PEP addition, which was 74.7% higher than the control; and the specific activity of pyruvate kinase decreased by 67.5%. Finally, the concentration of succinic acid was 29.1 g/L with the yield of 76.2%.
Actinobacillus ; metabolism ; Anaerobiosis ; Culture Media ; Culture Techniques ; methods ; Fermentation ; Phosphotransferases (Paired Acceptors) ; metabolism ; Succinic Acid ; metabolism

The protocorm-suspension-system of Cremastra appendiculata was founded by liquid-suspension culture. The factors to effect germination rate and seedling conversion rate of C. appendiculata synthetic seeds, such as synthetic coating materials, synthetic endosperm components, storing conditions and germination materials, etc. were studied. The result showed that the germination rate and seedling conversion rate of synthetic seeds were the highest on the MS solid-medium while using 4% sodium alginate + 2% CaCl2 + 2% chitosan as synthetic coating materials, with 1/2 MS liquid-medium + 0.2 mg x L(-1) NAA + 0.1 mg x L(-1) GA3 + 0.5 mg L(-1) BA + 0.4 mg x L(-1) penicillin + 10.0 mg x L(-1) endophyte extract +0.3% carbendazim powder + 0.2% sodium benzoate + 1.0% sucrose as synthetic endosperm. And the germination rate and seedling conversion rate of synthetic seeds could attain to 68% and 65% after 20 days storing at 4 degrees C. The germination rate and seedling conversion rate of synthetic seeds decreased to a great extent with increasing the storing temperature and prolonging storing time.
Culture Media ; metabolism ; Germination ; Orchidaceae ; growth & development ; metabolism ; Seeds ; growth & development ; metabolism ; Tissue Culture Techniques ; methods

OBJECTIVETo investigate the effects of several additives (sodium acetate, phenylalanine and amidocaproic acid) on glycyrrhizin production in Glycyrrhiza uralensis cells.

METHODThe different concentration of additives were administrated into the medium at the beginning of the culture. The glycyrrhizin content in G. uralensis cells was analyzed by HPLC.

RESULTThe lower sodium acetate concentration of 0.1 mmol x L(-1) enhanced the glycyrrhizin content by 2.4 times and the higher sodium acetate concentration resulted in the higher accumulation of cell biomass. Glycyrrhizin content increased slightly when the phenylalanine dosages increased gradually from 0.1-2 mmol x L(-1). The highest glycyrrhizin content of 14.10 microg x g(-1) was obtained with the addition of 2 mmol x L(-1) phenylalanine which was 3.60 times compared with the control. The addition of 0.1 mmol x L(-1) amidocaproic acid increased the glycyrrhizin content by 2. 24 times. With the increase of the concentration of amidocaproic acid, the glycyrrhizin content decreased slightly and the higher concentration of 2 mol x L(-1) inhibited the accumulation of glycyrrhizin.

CONCLUSIONThe addition of sodium acetate, phenylalanine and amidocaproic acid to the medium were effective approaches to enhance the glycyrrhizin content in G. uralensis cells.

Cell Culture Techniques ; Cells, Cultured ; Culture Media ; metabolism ; Glycyrrhiza uralensis ; metabolism ; Glycyrrhizic Acid ; metabolism

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.

Aeromonas ; metabolism ; Culture Media ; Flocculation ; Hydrogen-Ion Concentration ; Kaolin

Fatty acids (FA) are widely used as feed stocks for the production of cosmetics, personal hygiene products, lubricants and biofuels. Ogataea polymorpha is considered as an ideal chassis for bio-manufacturing, due to its outstanding characteristics such as methylotroph, thermal-tolerance and wide substrate spectrum. In this study, we harnessed O. polymorpha for overproduction of fatty acids by engineering its fatty acid metabolism and optimizing the fermentation process. The engineered strain produced 1.86 g/L FAs under the optimized shake-flask conditions (37℃, pH 6.4, a C/N ratio of 120 and an OD₆₀₀ of seed culture of 6-8). The fed-batch fermentation process was further optimized by using a dissolved oxygen (DO) control strategy. The C/N ratio of initial medium was 17.5, and the glucose medium with a C/N ratio of 120 was fed when the DO was higher than 30%. This operation resulted in a titer of 18.0 g/L FA, indicating the potential of using O. polymorpha as an efficient cell factory for the production of FA.
Culture Media ; Fatty Acids ; Fermentation ; Metabolic Engineering ; Saccharomycetales/metabolism*

OBJECTIVETo optimize the condition of callus of Cinnamonum camphora induced.

METHODGC and plant tissue culture method were applied in the study.

RESULTThe effect of callus induced and the growth of callus were different in MS medium with different proportion of hormone. The ration of callus induced was the highest and the growth of callus was the most prosperous in the MS medium with 4 mg x L(-1) 2,4-D and 0.2 mg x L(-1) 6-BA. It is found that callus induced by young leaf contained borneol, but callus induced by young stem not.

CONCLUSIONThe optimization of callus of C. camphora induced is using the MS medium with 4 mg x L(-1) 2,4-D + 0.2 mg x L(-1) 6-BA. Callus induced by young leaf can generate borneol.

Bornanes ; metabolism ; Cinnamomum camphora ; growth & development ; metabolism ; Culture Media ; Tissue Culture Techniques

OBJECTIVETo establish and optimize the rapid propagation system of Polygonum multiflorum, as well as explore method for induction and identification of autotetraploid.

METHODPropagation medium was optimized by orthogonal test. The buds were immersed in colchicine solution with different concentrations for different time to select induction conditions for autotetraploid of P. multiflorum.

RESULTThe most appropriate propagation medium was MS medium supplemented with 1.0 mg x L(-1) 6-BA, 0.3 mg x L(-1) NAA, and 0.4 mg x L(-1) PP333. That the buds were soaked in 0.2% colchicine solution for 30 h, or soaked in 0.3% colchicine solution for 18 h, was optimal condition to induce autopolyploid of P. multiflorum with induction rate as high as 16.7%.

CONCLUSIONRapid propagation of P. multiflorum could be achieved by tissue culture. Furthermore, colchicine was an effective inducer of polyploidy, and 25 tetraploid lines were obtained through chromosome identification. The experiment laid a foundation for the wild resource conservation, superior varieties breeding of P. multiflorum.

Chromosomes, Plant ; genetics ; Culture Media ; metabolism ; Polygonum ; genetics ; growth & development ; metabolism ; Tetraploidy ; Tissue Culture Techniques ; methods

Arachidonic acid, as an important polyunsaturated fatty acid, is identified as potential food additives or pharmaceuticals for their biological activities. In recent years, arachidonic acid production by Mortierella alpina is becoming a research highlight. The prophase relevant researches focused on the mutagenic breeding and fermentation optimization. With the depth of investigation, the advancement concerning pathway for the biosynthesis of arachidonic acid in Mortierella alpina has been made. In this review, we summarized the prophase work briefly. Mainly, we discussed the biosynthesis pathway of arachidonic acid, the key enzymes, the construction of transformation system and the genetic modification. In addition, the prospect of microorganism arachidonic acid production is put forward.
Arachidonic Acid ; biosynthesis ; Culture Media ; Culture Techniques ; methods ; Genetic Engineering ; methods ; Mortierella ; genetics ; metabolism

In order to improve the yield of bacterial cellulose (BC), the fermentation medium of BC-producing strain J2 (Gluconobacter) was optimized, and BC ultra-micro-structure was observed. Initially, Plackett-Burman design was employed to evaluate eight variables which were relevant to BC production. Three statistically significant parameters including yeast extract, ZnSO4, ethanol were selected and other 5 variables were not significant (P > 0.05). The optimized levels of three variables were defined by Box-Behnken design and response surface methodology (RSM). BC ultra-micro-structure was observed by scanning electron microscope (SEM) with cotton cellulose as comparison. The results indicated that the BC yield under the optimum fermentation medium was 11.52 g/100 mL, which was as 1.35 times as that under the original fermentation medium. The SEM photos manifested that bacterial cellulose ribbon, with a diameter less than 0.1 microm, was less than cotton cellulose ribbon. The bacteria inside the cellulose net were eliminated after the NaOH treatment.
Cell Culture Techniques ; Cellulose ; biosynthesis ; ultrastructure ; Culture Media ; chemistry ; Fermentation ; Gluconobacter ; cytology ; metabolism