Study on kinetics of two-stage cultivation of protocorm-like bodies from Dendrobium huoshanense for cell growth and synthesis of polysaccharides / 生物工程学报

Phosphate is an effective factor in the regulation of cell growth and accumulation of polysaccharides. The method for higher polysaccharide production has been obtained through feeding cultivation. The two-stage cultivation was proposed according to the characteristic of cell growth and the accumulation of polysaccharides in the suspension cultures of protocorm-like bodies from Dendrobium huoshanense. A kinetic model was developed to describe the cultivation process. The results indicate that the production of biomass and polysaccharides increases from 28.7g DW/L and 1.86g/L to 44.2g DW/L and 5.22g/L, respectively, and the content of polysaccharides increases from 6.4% to 11.9% . With the evaluated model parameters, the model appears to provide a description for the cultivation process.

Effect of spermine on cell growth and polysaccharide production in suspension cultures of protocorm-like bodies from Dendrobium huoshanense / 生物工程学报

The effect of outer spermine on cell growth, accumulation of polysaccharides and utilization of nutrient together with the intracellular polyamine contents were investigated in suspension cultures of protocorm-like bodies from Dendrobium huoshanense. The results indicated that spermine at 0.6 mmol/L was the most effective in increasing cell growth and polysaccharide synthesis. The specific growth rate of cell increased from 0.046d(-1) to 0.054d(-1), and the maximum dry weight and polysaccharide production reached 32.4g DW/L and 2.46g/L respectively, which were 1.32-fold and 1.31-fold that of the control on day 30. The titres of intracellular free polyamines were higher in the cultures treated with spermine than that of the control. Invertase and nitrate reductase activities were found to increase significantly in the cultured cells treated with spermine, which was beneficial to the utilization of carbon and nitrogen source.

Study on isoflavone active aglycone preparation by immobilized beta-glucosidase from Aspergillus niger / 生物工程学报

With sodium alginate as a carrier and glutaraldehyde as the crosslinking agent, an improved immobilization method of beta-glucosidase for production of soybean genistein was developed. As compared with entrapment or entrapment-crosslinkage, crosslinkage-entrapment that beta-glucosidase was treated with glutaraldehyde and then entrapped in sodium alginate remained high loading efficiency and activity recovery, Effects of bead sizes, concentrations of alginate and glutaraldehyde as well, on the loading efficiency and activity recovery were assessed. When compared with the free enzyme, the optimum temperature, pH value and Km of the immobilized beta-glucosidase were respectively shifted from 50 degrees C to 40 degrees C, 4.5 to 4.0 and 2.57 microg/mL to 2.02 miocrog/mL. The stabilities of the immobilized beta-glucosidase were considerably better than that of the native enzyme. The immobilized beta-glucosidase was employed to genistein production, 84.94% of the activity and 56.04% of conversion were kept after consecutive use of 6 times.

Species diversity of Lachnum (Helotiales, Hyaloscyphaceae) from temperate China / 浙江大学学报（英文版）（B辑：生物医学和生物技术）

Twenty-three temperate China species of Lachnum, Lachnum abnorme, L. angustum, L. brevipilosum, L. calosporum, L. calyculiforme, L. carneolum, L. ciliare, L. controversum, L. flavidulum, L. cf. fushanese, L. indicum, L. kumaonicum, L. lushanese, L. minutum, L. montanum, L. cf. pteridophyllum, L. pygmaeum, L. sclerotii var. sclerotii, L. sclerotii var. sichuanense, L. subpygmeaum, L. tenuissimum, L. virgineum and L. willisii are reported, whose main characteristics are given in a formula of the described species, some of which are discussed below.

Effect of phosphate on growth and polysaccharide production by suspension cultures of protocorm-like bodies of Dendrobium huoshanense / 生物工程学报

The effect of inorganic phosphate on cell growth, accumulation of polysaccharides together with nutrient utilization was investigated in suspension cultures of protocorm-like bodies of Dendrobium huoshanense. Thirty-day-old cells were transferred into liquid medium with the inoculum density of 100 g/L cells. The results indicate that the optimal concentration of phosphate in medium for cell growth of protocorm-like bodies of Dendrobium huoshanense was 2.5 mmol/L and biomass was 496.5 g/L (fresh weight). Phosphate was a limited factor for cell growth and there was relationship between the levels of intracellular phosphate and cell growth. 2.5 mmol/L of medium phosphate was beneficial to the absorption of carbohydrate and nitrate source. 0.312 mmol/L of medium phosphate was better for accumulation of polysaccharides and production of polysaccharides was 2.22 g/L at 36 d.

Optimization for isoflavone production in Maackia amurensis suspension cells based on neural networks and accelerating genetic algorithm / 生物工程学报

The medium for isoflavone production in Maackia amurensis suspension cells has been optiwised through the artificial neural networks (ANNs) and the real coding based accelerating genetic algorithm (RAGA). Among the ingredients of the medium, nitrogen sources and plant growth regulators were found to be the main factors affecting the production of isoflavone genistein. (NH4)2SO4, KNO3, 2,4-D and 6-BA, 100 approximately 800 mg/L, 1500 approximately 3000 mg/L, 0 approximately 3 mg/L and 0 approximately 1 mg/L respectively, significantly increased genistein yield, in the ranges of effective concentrations. The random ten combinations of these four components generated by RAGA as input data and the genistein yields of ten combinations as output data were used for ANNs-RAGA (the artificial neural networks associated with the accelerating genetic algorithm) modeling. The resultant model showed a high fit between the experimental data and calculating values by ANNs-RAGA. Based on the prediction of the model, the optimum combination of four factors for genistein production was determined on 149.68 mg/L for (NH4)2SO4, 2936.10 mg/L KNO3, 0.01 mg/L 2,4-D and 0.19 mg/L 6-BA. When cells were cultured in the optimized medium, their capability of genistein production was remarkably enhanced to 14.13 mg/L, which was about 19 times higher than that in the original medium. The relative discrepancy between the experimental value and the predictive value of genistein yield from the optimized medium was 7.38%.

Callus formation and its isoflavonoid accumulation in Maackia amurensis / 中国中药杂志

<p><b>OBJECTIVE</b>To obtain Maackia amurensis callus and investigate some factors influencing total isoflavonoid production in callus.</p><p><b>METHOD</b>Different media were used for callus induction from cotyledonary and hypocotyl explants. Total isoflavonoid content was determined by UV spectrophotometer.</p><p><b>RESULT</b>Medium types and hormone combinations influenced both callus formation and their developmental states. MS medium supplemented with NAA/BA or containing 2,4-D was suitable for callus induction from cotyledonary explants. Among the basal media tested, MS, N6 and B5 were suitable for cotyledonary callus formation and SH for hypocotyl callus formation. The formed callus could synthesize isoflavones. Media containing NAA were suitable for isoflavonoid production in cotyledonary callus and media containing 2,4-D/BA were suitable for hypocotyl callus, but 2,4-D/KT at high concentration inhibited the isoflavonoid accumulation in hypocotyl and coytledonary calli. According to the developmentally morphological characters, the formed callus could be classified into four types. II-type callus with yellow in color and friability in texture showed the highest accumulation of isoflavones.</p><p><b>CONCLUSION</b>The influences of medium type and hormone combinations on Maackia amurensis callus formation are reflected in both developmentally morphological characters and isoflavonoid accumulation of calli. Yellow, friable callus induced from cotyledonary and hypocotyl explants in MS or N6 medium supplemented with 2,4-D and BA exhibit the optimum growth and isoflavonoid production.</p>

Suspension culture of protocorm-like bodies from the endangered medicinal plant Dendrobium huoshanenese / 中国中药杂志

<p><b>OBJECTIVE</b>To investigate the characteristics of growth, and water-soluble polysaccharide and total alkaloid accumulation in protocom-like bodies (PLBs) of Dendrobium huoshanenese in liquid culture system.</p><p><b>METHOD</b>PLBs were suspended in liquid medium and growth kinetics was analyzed. Water-soluble polysaccharide and total alkaloid content in PLBs were determined by colorimetry.</p><p><b>RESULT</b>PLBs were induced from stem explants of D. huoshanenese regenerants cultured on MS medium supplemented with NAA or NAA and KT at different concentrations. Basal MS medium was suitable for propagation of PLBs. When PLBs were suspended in liquid medium, mumax was 0.044.d-1, t(d) was 15.8 d and the optimum growth time was 4 weeks. Water-soluble polysaccharide and total alkaloid contents in PLBs were 3.75% and 0.0261%, respectively.</p><p><b>CONCLUSION</b>PLBs in liquid culture system show a potential for rapid growth and high metabolite synthesis, which provides possibility for exploiting resources of D. huoshanenese by large scale culture of PLBs.</p>

The Screening of Alcohol Dehydrogenase (ADH) Mutant of Rhizopus oryzae / 微生物学通报

During L-lactic acid fermentation with Rhizopus oryzae,there existed a branch pathway by which pyruvate was transformed to eth- anol catalyzed by pyruvate decarboxylase(PDC)and alcohol dehydrogenase(ADH),thus decreasing the flux of pyruvate to lactic acid.In this study,the spores of Rhizopus oryzae AS3.3462 mutagenized with nitrosoguanidine(NTG),the appropriate dosage was 0.15 mg/mL and the lethal rate was 70%～80%.Two mutants,named mut-1 and mut-2,with decreased ADH activity were screened out by yeast peptone dextrose(YPD)agar medium containing allyl alcohol.These two mutants had decreased ADH activities of 41.63% and 50.29% compared with the parent strain.The fermentation behavior after 72h showed that the yields of ethanol produced by mut-1 and mut-2 were 4.87g/L and 6.56g/L respectively,while the wild type strain was 28.9g/L,and the lactate concentrations of mut-1 and mut-2 also increased from 40.31g/L to 54.45g/L and 44.07 g/L,respectively.It is also found that mut-1 and mut-2 had a high reducing sugar consumption rate and biomass accumulation than its present strain

The Screening and Identification of Strains Biodegrading Superabsorbent / 微生物学通报

Using the superabsorbent of starch graft sodium acrylate copolymer as the only carbon source, 4 excellent strains which can utilize the synthesized superabsorbent were obtained from soil after one month's screening and purification, then the taxa of the strain were identified, i.e., two kind of actinomycetes, yeast and mould.The result shows that the superabsorbent can be degraded successfully.

SCREENING AND CHARACTERIZATION OF A PHENOL-DEGRADING BACTERIUM / 微生物学通报

A strain ph 16 , that could effectively degrade phenol,was isolated from sewer sludge of printing and dyeing plant. The preliminary identification sugg ested that the strain belongs to Micrococcus sp. The strain could resist to phenol up to 1.5 g/L. The efficient biodegradation of phenol occurred when th e strain was cultured in the medium (pH 7.0) containing 1.0 g/L phenol under 35℃, wh er e the highest degradation rate reach 99.6% after 36 hours. This strain, when t re ated with some heavy metal ions such as Hg +、Co 2+ and Ag 2+ , showe d the significant inhibition of phenol degradation by 74.2%～100%. The kinetic s of phenol degradation during culture of the strain was also explored.