Starch is composed of glucose units linked by α-1, 4-glucoside bond and α-1, 6-glucoside bond. It is the main component of foods and the primary raw material for starch processing industry. Pullulanase can effectively hydrolyze the α-1, 6-glucoside bond in starch molecules. Combined with other starch processing enzymes, it can effectively improve the starch utilization rate. Therefore, it has been widely used in the starch processing industry. This paper summarized the screening of pullulanase-producing strain and its encoding genes. In addition, the effects of expression elements and fermentation conditions on the production of pullulanase were summarized. Moreover, the progress in crystal structure elucidation and molecular modification of pullulanase was discussed. Lastly, future perspectives on pullulanase research were proposed.
Glycoside Hydrolases/genetics* ; Starch/metabolism*

In the present study, we developed a two-liquid phase fermentation system by adding 1% n-dodecane as oxygen-vector to enhance the microbial lipids productivity of Trichosporon fermentans using cassava starch hydrolysate. Results suggest that the oxygen-vector could alleviate the oxygen shortage in flask fermentation. The cell mass and lipids concentration were 101.2 g/L and 50.28 respectively in 2 L fermenter with the presence of 1% n-dodecane. Additionally, gas chromatography analysis also reveals that the microbial lipids produced by T. fermentans contained a higher percentage of saturated fatty acid in the oxygen-vector case.
Alkanes ; chemistry ; Biofuels ; Fermentation ; Industrial Microbiology ; methods ; Lipids ; biosynthesis ; Manihot ; metabolism ; Starch ; metabolism ; Trichosporon ; genetics ; metabolism

OBJECTIVETo study scutellarin starch microspheres' permeability through nasal mucosa of different animals in vitro.

METHODThe Franz diffusion cell method was used to experiment the permeability test (n = 4), taking fresh nasal mucosa of dog, swine and domestica in vitro as permeation barrier separately, with scutellarin starch microspheres (scutellarin 0.25 mg) above them, and blank pH 6.8 PBS as absorption liquid to detemine the scutellarin by HPLC.

RESULTThe permeability coefficient of scutellarin starch microspheres through nasal mucosa of dog, swine and domestica in vitro were (5.295 +/- 0.637) x 10(-3) (4.065 +/- 1.140) x 10(-3), (1.855 +/- 0.150) x 10(-3) cm x mL(-1) separately. The permeability coefficient order of scutellarin starch microspheres through nasal mucosa of different animals in vitro is dog > swine > domestica, and there are significant differences between the permeability coefficient of scutellarin starch microspheres through nasal mucosa of dog, swine in vitro, and that through nasal mucosa of swine and domestica in vitro.

CONCLUSIONDrugs in scutellarin starch microspheres could permeate through the above-mentioned nasal mucosa in vitro. There might be different permeability coefficient among different species.

Animals ; Apigenin ; pharmacokinetics ; Dogs ; Glucuronates ; pharmacokinetics ; Microspheres ; Nasal Mucosa ; metabolism ; Permeability ; Starch ; pharmacokinetics ; Swine ; Swine, Miniature

Microbial oil, as raw material for biodiesel, can be produced by Trichosporon cutaneum B3 using cassava starch hydrolysate. Batch cultures demonstrated that there was little inhibitory effect with the concentration of cassava starch hydrolysate up to 90 g/L. The favorable initial pH, C/N molar ratio, nitrogen source and its concentration were 6.0, 116, yeast extract and 3.0 g/L, respectively. Under the optimized conditions, dry biomass reached 15.2 g/L and lipid content reached 40.9% after culture for 144 h in flask. Batch cultures in a 2 L stirred-tank fermenter were run for 44 h and resulted in dry biomass, lipid content and lipid yield of 28.7 g/L, 42.8% and 12.27 g/L, respectively. The chemical compositions of biodiesel prepared from lipids of T cutaneum B3 mainly included palmitic acid methyl ester, stearic acid methyl ester, oleic acid methyl ester and linoleic acid methyl ester etc., and its main physicochemical properties were in compliance with relevant national diesel standards. Therefore, the biodiesel prepared from lipids of T cutaneum B3 can serve as a potential fossil fuel alternatives.
Biofuels ; Culture Techniques ; methods ; Fermentation ; Industrial Microbiology ; methods ; Lipids ; biosynthesis ; Manihot ; metabolism ; Starch ; metabolism ; Trichosporon ; growth & development ; metabolism

To optimize the preparation conditions of porous starch The porous starch was used to powder coix seed oil. Porous starch was made of maize starch by using compound enzymes of glucoamylase and alpha-amylase. The preparation process was optimized through orthogonal test design with oil absorption rate to salad oil as indexes. The effect of different dosages of porous starch on yield of triglyceride by powdering coix seed oil was studied. The triglyceride release behaviors and fluidity of powdered coix seed oil were also studied. The results showed that the optimum conditions for preparation of porous maize starch were as follows, the mass radio of glucoamylase to a-amylase was 3:1, the temperatures was 55 degrees C, pH was 5.0, and hydrolysis time was 12 h. Under these conditions, the oil absorption rate to salad oil was 98.5% for porous maize starch. Porous starch was used to power coix seed oil. When porous starch to coix seed oil was 4:1, the triglyceride yield of powering coix seed oil was up to 97.02%. The fluidity of powdered coix seed oil was favorable and control released. The preparation of powdered liquid oil with porous starch had many advantages such as simple production technology, convenient operation, low cost and was worth generalizing.
Coix ; chemistry ; metabolism ; Plant Oils ; chemistry ; metabolism ; Porosity ; Powders ; chemistry ; metabolism ; Seeds ; chemistry ; metabolism ; Starch ; chemistry ; metabolism ; Triglycerides ; metabolism ; Zea mays ; chemistry ; metabolism

In order to investigate the enzyme production mechanism of yak rumen-derived anaerobic fungus Orpinomyces sp. YF3 under the induction of different carbon sources, anaerobic culture tubes were used for in vitro fermentation. 8 g/L of glucose (Glu), filter paper (Flp) and avicel (Avi) were respectively added to 10 mL of basic culture medium as the sole carbon source. The activity of fiber-degrading enzyme and the concentration of volatile fatty acid in the fermentation liquid were detected, and the enzyme producing mechanism of Orpinomyces sp. YF3 was explored by transcriptomics. It was found that, in glucose-induced fermentation solution, the activities of carboxymethyl cellulase, microcrystalline cellulase, filter paper enzyme, xylanase and the proportion of acetate were significantly increased (P < 0.05), the proportion of propionate, butyrate, isobutyrate were significantly decreased (P < 0.05). The results of transcriptome analysis showed that there were 5 949 differentially expressed genes (DEGs) between the Glu group and the Flp group, 10 970 DEGs between the Glu group and the Avi group, and 6 057 DEGs between the Flp group and the Avi group. It was found that the DEGs associated with fiber degrading enzymes were significantly up-regulated in the Glu group. Gene ontology (GO) function enrichment analysis identified that DEGs were mainly associated with the xylan catabolic process, hemicellulose metabolic process, β-glucan metabolic process, cellulase activity, endo-1,4-β-xylanase activity, cell wall polysaccharide metabolic process, carbohydrate catabolic process, glucan catabolic process and carbohydrate metabolic process. Moreover, the differentially expressed pathways associated with fiber degrading enzymes enriched by Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were mainly starch and sucrose metabolic pathways and other glycan degradation pathways. In conclusion, Orpinomyces sp. YF3 with glucose as carbon source substrate significantly increased the activity of cellulose degrading enzyme and the proportion of acetate, decreased the proportion of propionate, butyrate and isobutyrate. Furthermore, the degradation ability and energy utilization efficiency of fungus in the presence of glucose were improved by means of regulating the expression of cellulose degrading enzyme gene and participating in starch and sucrose metabolism pathway, and other glycan degradation pathways, which provides a theoretical basis for the application of Orpinomyces sp. YF3 in practical production and facilitates the application of Orpinomyces sp. YF3 in the future.
Animals ; Cattle ; Neocallimastigales/metabolism* ; Anaerobiosis ; Rumen/microbiology* ; Propionates/metabolism* ; Isobutyrates/metabolism* ; Cellulose/metabolism* ; Fungi ; Starch/metabolism* ; Glucose/metabolism* ; Acetates ; Sucrose/metabolism* ; Cellulases ; Cellulase

We used four strains (Y1, Y2, M1 and M2) to screen out the high lipid production strains. We first adopted cell morphology and cytochemical methods (Sudan III dyeing technique) to observe intracellular characteristics. Observation results indicated that M2 strain had the potential lipid accumulation capacity. To prove this, lipid content of these strains was determined by soxhlet extraction. One strain (M2) was found to produce lipids up to 53.09%. In order to increase the production of oleaginous microorganism, the effects of hydrolysate concentration, nitrogen source, pH, fermentation temperature and time on cell growth and lipid accumulation were studied. The optimal fermentation conditions were obtained as follows: corn starch byproduct hydrolysate concentration at 10(o) Bx as carbon source; NaNO3 as nitrogen source at 0.2%; initial pH of 6.0; temperature at 28 degrees C, cultivated for 6 d. Under these conditions, M2 strain accumulated lipids up to 75.21% on a cellular biomass basis with biomass yield of 30.40 g/L, and the corresponding lipid production reached 22.86 g/L. GC analysis demonstrated that the fatty acid composition of the lipid was similar to that of vegetable oil, which mainly contained 16-and 18-carbon fatty acids. Thus, microbial lipid is a promising material for biodiesel production, and its unsaturated fatty acid content reached around 68%. These unsaturated fatty acids show great potential applications in food, medicine and cosmetics industries.
Biomass ; Culture Media ; Fatty Acids ; analysis ; biosynthesis ; Fermentation ; Hydrogen-Ion Concentration ; Industrial Microbiology ; Starch ; metabolism ; Temperature ; Yeasts ; growth & development ; metabolism

OBJECTIVETo observe the effects of resistant starch (RS) on insulin resistance (IR) in type 2 diabetes mellitus patients.

METHODSAll 40 patients with type 2 diabetes mellitus were randomly divided into two groups: Group A and Group B. Cross-design of two stages (I, II) was used during observation. Group A received RS 30 g/d as an intervention group for ahead of 4 weeks ( I stage) , while group B as a control group. Group B was given RS in late 4 weeks (II stage), while Group A as served control group. Blood was taken the first day and on the latest day in each stage. Fasting blood glucose (FBG), post blood glucose (PBG), fructosamine (FMN), total cholesterol (TC), triglyceridemic (TG), insulin sensitive index (ISI), and body mass index (BMI) were measured, respectively.

RESULTSAs Compared with the control group, ISI was higher and FBG, PBG, TC, TG, FMN and BMI were significantly lower in intervention group (P < 0.05).

CONCLUSIONRS should be effective in improving IR of type 2 diabetes mellitus patients.

Adult ; Diabetes Mellitus, Type 2 ; diet therapy ; metabolism ; Female ; Humans ; Insulin ; metabolism ; Insulin Resistance ; Male ; Middle Aged ; Starch ; administration & dosage

Production of bioethanol using starch as raw material has become a very prominent technology. However, phytate in the raw material not only decreases ethanol production efficiency, but also increases phosphorus discharge. In this study, to decrease phytate content in an ethanol fermentationprocess, Saccharomyces cerevisiae was engineered forheterologous expression of phytase on the cell surface. The phy gene encoding phytase gene was fused with the C-terminal-half region of α-agglutinin and then inserted downstream of the secretion signal gene, to produce a yeast surface-display expression vector pMGK-AG-phy, which was then transformed into S. cerevisiae. The recombinant yeast strain, PHY, successfully displayed phytase on the surface of cells producing 6.4 U/g wet cells and its properties were further characterized. The growthrate and ethanol production of the PHY strain were faster than the parent S. cerevisiae strain in the fermentation medium by simultaneous saccharification and fermentation. Moreover, the phytate concentration decreased by 91% in dry vinasse compared to the control. In summary, we constructed recombinant S. cerevisiae strain displaying phytase on the cell surface, which could effectively reduce the content of phytate, improve the utilization value of vinasse and reduce the discharge of phosphorus. The strain reported here represents a useful novel engineering platform for developing an environment-friendly system for bioethanol production from a corn substrate.
6-Phytase ; metabolism ; Biofuels ; Ethanol ; chemistry ; Fermentation ; Industrial Microbiology ; Saccharomyces cerevisiae ; metabolism ; Starch ; chemistry ; Zea mays ; chemistry

Production of biofuels such as ethanol from non-grain crops may contribute to alleviating the global energy crisis and reducing the potential threat to food security. Tobacco (Nicotiana tabacum) is a commercial crop with high biomass yield. Breeding of starch-rich tobacco plants may provide alternative raw materials for the production of fuel ethanol. We cloned the small subunit gene NtSSU of ADP-glucose pyrophosphorylase (NtAGPase), which controls starch biosynthesis in tobacco, and constructed a plant expression vector pCAMBIA1303-NtSSU. The NtSSU gene was overexpressed in tobacco upon Agrobacterium-mediated leaf disc transformation. Phenotypic analysis showed that overexpression of NtSSU gene promoted the accumulation of starch in tobacco leaves, and the content of starch in tobacco leaves increased from 17.5% to 41.7%. The growth rate and biomass yield of the transgenic tobacco with NtSSU gene were also significantly increased. The results revealed that overexpression of NtSSU gene could effectively redirect more photosynthesis carbon flux into starch biosynthesis pathway, which led to an increased biomass yield but did not generate negative effects on other agronomic traits. Therefore, NtSSU gene can be used as an excellent target gene in plant breeding to enrich starch accumulation in vegetative organs to develop new germplasm dedicated to fuel ethanol production.
Biomass ; Gene Expression Regulation, Plant ; Plant Breeding ; Plant Leaves/genetics* ; Plants, Genetically Modified/metabolism* ; Starch ; Tobacco/metabolism*