Antisepsis and Fresh-keeping Effects of Natamycin Coating Compounds Treatment on Red Global Grape

The aim was to research fresh-keeping effects of natamycin on cold-pre- served grape. Red globe grapes were processed with compound coating liquid of chitosan with mass fraction at 1% and natamycin with mass fractions at 0.20% （T1）, 0.40% （T2） and 0.60% （T3）, respectively. Grapes processed with water （CK3） and 1% chitosan （CK2） were taken as control groups. Rotten rate, seed shattering rate, mass loss rate, respiratory intensity and related physiological quality in test and control groups were compared. The results indicated that respiratory intensity, mass loss rate, rotten rate and seed shattering rate in CK1 were all higher than those in CK2. In addition, T1, T2 and T3 were lower in the indices than CK1 and CK2, but still kept at a high level in fruit hardness. Furthermore, mass fractions of Vc and titratable acid declined more slowly in T1, T2 and T3, compared with CK1 and CK2. Natamycin better preserved grapes and prolonged storage period. In general, natamycin with mass fraction at 0.4% proved best in fresh-keeping.

抗菌素natamycin对酵母菌生长的影响

考察了natamycin对酵母菌生长繁殖的影响 ,确定了其最低抑菌浓度及最佳添加时间。结果表明 :natamycin对酵母的生长繁殖有明显的抑制作用 ,其最小抑菌浓度为 2 5 μg·mL-1;其抑菌效果与其浓度成正相关 ,与加入natamycin时酵母菌的初始活菌数成负相关 ;在酵母菌生长延迟期加入natamycin抑菌效果明显好于稳定期加入。

Antifungal efficacy of natamycin in experimental fusarium solani keratitis

AIM: To evaluate the efficacy of topical administration Natamycin, which is produced by China, in an experimental rabbit model of Fusarium solani keratitis, to provide experimental basis for the application of clinical safety. METHODS: Fusarium solani was induced in the right eye of 30 New Zealand rabbits. Forty-eight hours after inoculation, the animals were divided into 3 different treatment groups, 10 rabbit eyes of each group: Group 1 (Natamycin) treated with topical Natamycin, group 2 (Natacyn) treated with topical Natacyn, group 3 (control) treated with topical saline solution. The eyes of each group was examined clinically with slit lamp using ulcer scoring system on day 4, 10, 15, and 21 for status of healing, corneal vascularisation, iritis, hypopyon and macular nebula. The findings were recorded on day 10 and day 21. RESULTS: Ulcer score on day 10, day 15, day 21: The score of Natamycin group are 1.45 +/- 0.16, 1.08 +/- 0.11, 0.70 +/- 0.40. The score of Natacyn group are 1.35 +/- 0.12, 1.10 +/- 0.12, 0.65 +/- 0.35. the score of control group are 1.30 +/- 0.08, 3.63 +/- 0.28, 3.80 +/- 0.16. Natamycin group and Natacyn group were different from control group (P <0.01). There is no difference between Natamycin group and Natacyn group. Status of healing on day 10 and day 21: The cure rate of the Natamycin group is 90% on day 10, and 100% on day 21. The cure rate of the Natacyn group is 80% on day 10, and 100% on day 21.Natamycin group and Natacyn group were different from control group (P<0.01). There is no difference between Natamycin group and Natacyn group. Corneal vascularisation, iritis, hypopyon and macular nebula on day 10 and day 21: in Natamycin group, the number of the eyes which have Corner vascularisation, iritis, hypopyon and macular nebula are 2,0,0,2. In Natacyn group, the number of the eyes which have Corner vascularisation, iritis, hypopyon and macular nebula are 1,0,0,2. In control group, the number of the eyes which have Corner vascularisation, iritis, hypopyon and macular nebula are 9,9,8,9.Natamycin group and Natacyn group were different from control group (P<0.01). There is no difference between Natamycin group and Natacyn group. CONCLUSION: Natamycin was found to be effective in fungal keratitis, similar to Natacyn, and it can stop the corner vascularisation, iritis, hypopyon and macular nebula to happen. Natamyin manufactured in China is effective against fungal keratitis, with esay availability and low toxicity in its use.

Natamycin in the treatment of fungal keratitis : a systematic review and Meta-analysis

AIM: To review published clinical studies examining the effect of natamycin in the treatment of fungal keratitis.METHODS: We selected the publications in CENTRAL,MEDLINE, EMBASE, CNKI, and CBM. This study systematically reviewed published randomized controlled trials(RCTs) that compared natamycin to other antifungal agents, and conducted feasible Meta-analysis of efficacy results using Revman 5.2 software.RESULTS: We included seven trials which were mainly carried out in developing countries of Asia, with five trials conducted in India, one each in China and Bangladesh. A total of 804 participants were randomized to following comparisons: 2% econazole versus 5%natamycin showed little difference in the effects of treatment of fungal keratitis [RR =0.99, 95% confidence interval(CI), 0.8 to 1.21]; chlorhexidine gluconate versus5% natamycin indicated that the results on healing of the ulcer at 21 d was less conclusive(RR=0.77, 95% CI, 0.55 to 1.08; I2=0%); 1% voriconazole versus 5% natamycin suggested that natamycin treatment appeared to be significantly better outcomes than voriconazole(regression coefficient =-0.18 log MAR; 95% CI,-0.30 to-0.05; P =0.006), especially in Fusarium cases(regression coefficient=-0.41 log MAR; 95% CI,-0.61 to-0.20; P 【0.001);natamycin versus fluconazole showed a significant difference in cure rate(χ2=5.048, P 【0.05) and natamycin group was more effective than fluconazole in average period of therapy(t =7.94, P 【0.01).CONCLUSION: Natamycin was a preferable choice in the treatment of fungal keratitis, especially in the early period of Fusarium cases.

天然食品防腐剂Natamycin的生产工艺及应用

本文介绍了天然食品防腐剂Natamycin的生产工艺,对其进行了安全性评价,阐述了其在食品中的应用现状。

Space-flight Mutation of Streptomyces gilvosporeus for Enhancing Natamycin Production

Mutants of the strain producing natamycin, Streptomyces gilvosporeus, were obtained after space-flight mutation. With respect to the sand spores and slant spores, the mutation ratios were up to 67.6% and 78.3% and the survival ratio was 43.1% and 3.0%, respectively. An improved mutant producing natamycin, S. gilvosporeus LK-45, was screened, which showed natamycin productivity of 1420mg·L^-1. A mutant resistant to 2-deoxy glucose, S.gilvosporeus LK-119, was further obtained using a＇rational screening procedure. The natamycin productivity of 1940mg·L^-1 was achieved when glucose was used as the carbon source.

Effects of Fed-batch and Nitrogen-deficient Culture on Lipid Yield of Chlorella sp.

[Objective] This study was to realize high-density culture of Chlorella sp. as well as the culture with high lipid yield. [Method] Through analyzing the growth curve of Chlorella sp. cells, dextrose consumption curve, change curves of pH and dissolved oxygen, a fed-batch culture was conducted, followed by a nitrogen-deficient culture aiming at accumulating the lipids in Chlorella sp. cells when a high density of Chlorella sp. cells was obtained. [Result] After four batches of feeding were pro- vided, the biomass of Chlorella sp. reached up to 65.25 g/L, and the lipid content increased from 42.75% to 63.82% in Chlorella sp. cells, with the yield of 43.37 g/L in the following 12 hours of nitrogen-deficient culture. [Conclusion] Reasonable fed- batch can significantly improve the biomass of Chlorella sp., and the nitrogen-defi- cient culture further raises the lipid yield of Chlorella sp.

The Fluorescence Immunochromatographic Strips for Natamycin and Its Application in Food Safety Detection

A fluorescence immunochromatographic strip was developed in this study for natamycin detection in food. The results showed that the best amount of labeled antibody was 10 μg, for every 50 μl of fluorescent microspheres with a 2.5%(w/v) concentration. This labeled antibody was diluted for 10 times, and the diluted solution was dispensed into conjugate pad at the amount of 3 μl/cm. The concentrations of natamycin labeled BSA for test line and goat anti-mouse IgG for control line were 2.0 and 1 mg/ml, respectively, which performed best. With the best conditions, the limit of detection was 1 ng/ml, the linearity ranged from 2 to 100 ng/ml, the recovery was about 80% to 120%, and the CV was below 23%.

Development and Characterisation of Natamycin Mini-Matrices Prepared by Hot-Melt Extrusion for Vaginal Delivery

In this study, bioadhesive mini-matrices of natamycin were prepared for vaginal application by hot-melt extrusion. In addition, melt viscosity measurements, thermogravimetric analysis, in vitro drug release studies and in vitro mucoadhesion test were performed. High molecular weight grades of KlucelTM hydroxypropylcellulose were used as a thermoplastic polymer. TEC and PEG 400 were chosen as plasticizer. According to the obtained results of melt viscosity measurements, the maximum torque of extrudates prepared using PEG 400 increased with increasing drug loading. The thermo-gravimetric analyses showed that natamycin is stable up to 198℃ and this result gives the opportunity to hot melt extrussion process at 90℃. In vitro drug release results showed that the release was extended up to 72 hours and drug release rate increased with increasing drug loading. In respect to the in vitro mucoadhesion test results, the values of work of mucoadhesion were found high as 771,977 mN.mm, 753,199 mN.mm, 686,356 mN.mm for the prepared hot melt extruded mini-matrices. Our results showed that the developed formulations were found worthy of further studies.

Nisin,Natamycin对调理狭鳕鱼片贮藏品质的影响

研究Nisin、Natamycin对调理狭鳕鱼片贮藏品质的影响。不同处理狭鳕鱼片在4℃冷藏条件下腌制24h后,测定其pH值、TVB-N值、组胺、大肠菌群及菌落总数。结果表明:Nisin和Natamycin对于调理狭鳕鱼片的pH值、挥发性盐基氮、微生物和组胺均优于空白样品;Natamycin对于调理狭鳕鱼片的pH值、微生物和组胺均优于Nisin处理的样品;Nisin对于调理狭鳕鱼片的挥发性盐基氮指标优于Natamycin;Nisin和Natamycin对冷藏调理狭鳕鱼片具有延长贮存期的特点,Natamycin的效果更为明显。分析得到结论:在0~4℃下,狭鳕鱼块的保质期在16天,两种抑菌剂使保鲜期延长了1~2天,相同状态下在这段时间的Natamycin效果略优于Nisin。

Process Control for Production of Human-like Collagen in Fed-batch Culture of Escherichia coli BL 21

Recombinant E. coli BL 21 was cultivated in high cell density to produce human-like collagen. The effects of the feeding of nitrogen source, controlled by an auto on/off-feeding mode with two different cycles of 0.5min and 4min intervals, oxygen-enrichment methods and inducement strength on the cell yield and human-like collagen production were investigated. The studies showed that nitrogen source feeding in fast cycle could result in higher human-like collagen production than that in slow cycle; and the feedback regulation of glucose, increase of the pressure of fermentation bioreactor, and supply of oxygen-enriched air could all increase cell yield and human-like collagen production. The effects of inducement strength on protein expression were found important. When OD600 reached 90-100, the cultivation temperature was increased to 42℃ to begin induction for 2-3 h, and then shifted to 39℃ for 5-6h induction, the cell density and human-like collagen production could reach 96g·L-1 [DCW (dry cell mass)] and 19.8% (g·g-1 DCW) respectively.

Batch and fed-batch production of butyric acid by Clostridium butyricum ZJUCB

The production of butyric acid by Clostridium butyricum ZJUCB at various pH values was investigated. In order to study the effect of pH on cell growth, butyric acid biosynthesis and reducing sugar consumption, different cultivation pH values ranging from 6.0 to 7.5 were evaluated in 5-L bioreactor. In controlled pH batch fermentation, the optimum pH for cell growth and butyric acid production was 6.5 with a cell yield of 3.65 g/L and butyric acid yield of 12.25 g/L. Based on these results, this study then compared batch and fed-batch fermentation of butyric acid production at pH 6.5. Maximum value (16.74 g/L) of butyric acid concentration was obtained in fed-batch fermentation compared to 12.25 g/L in batch fermentation. It was concluded that culti- vation under fed-batch fermentation mode could enhance butyric acid production significantly (P<0.01) by C. butyricum ZJUCB.

Run-to-run Optimization for Fed-batch Fermentation Process with Swarm Energy Conservation Particle Swarm Optimization Algorithm

An iterative optimization strategy for fed-batch fermentation process is presented by combining a run-to-run optimization with swarm energy conservation particle swarm optimization (SEC-PSO). SEC-PSO, which is designed with the concept of energy conservation, can solve the problem of premature convergence frequently appeared in standard PSO algorithm by partitioning its population into several sub-swarms according to the energy of the swarm and is used in the optimization strategy for parameter identification and operation condition optimization. The run-to-run optimization exploits the repetitive nature of fed-batch processes in order to deal with the optimal problems of fed-batch fermentation process with inaccurate process model and unsteady process state. The kinetic model parameters, used in the operation condition optimization of the next run, are adjusted by calculating time-series data obtained from real fed-batch process in the run-to-run optimization. The simulation results show that the strategy can adjust its kinetic model dynamically and overcome the instability of fed-batch process effectively. Run-to-run strategy with SEC-PSO provides an effective method for optimization of fed-batch fermentation process.

Production of Ammonium Lactate by Fed-batch Fermentation of Rhizopus oryzaefrom Corncob Hydrolysate

L-(+)-Lactic acid production from corncob hydrolysate as a cheap carbohydrate source by fed-batch fermentation of Rhizopus oryzaeHZS6 was studied. After 96 h of fermentation in a 5 L fermentor, the final concentration of ammonium L-(+)-lactate, average productivity(based on initial xylose concentration) and maximum dry cell weight were 132.4 g/L, 1.38 g/(L·h), and 8.9 g/L respectively. The optical purity of L-(+)-lactate was 98.8%.

Improved 5-Aminolevulinic Acid Production with Recombinant Escherichia coli by a Short-term Dissolved Oxygen Shock in Fed-batch Fermentation

5-Aminolevulinic acid （ALA） is a common precursor for tetrapyrrole compounds in all kinds of organ isms and has wide applications in agriculture and medicines. In this study, a new strategy, i.e. short-term dissolved oxygen （DO） shock during aerobic fermentation, was introduced to produce 5-aminolevulinic acid with a recombi-nant E. coli. Effects of duration time of DO shock operation on plasmid concentration, intracellular ALA synthase （ALAS） activity and ALA production were investigated in Erlenmeyer shake flasks. The results indicated that both ALAS activity and ALA yield were enhanced in an anaerobic operation of 45 rain in the early exponential phase during fermentation, while they decreased when the anaerobic operation time was further increased to 60 rain. The DO shock protocol was confirmed with the fed-batch fermentation in a 15 L fermenter and the ALA production achieved 9.4 g.L-1 （72 mmol.L-1）, which is the highest yield in the fermentation broth reported up to now.

Strategies for Optimizing Feed Rate of Fed-Batch Yeast Fermentation by Fuzzy-Neural Network

In this paper,a novel fuzzy neural network model,in which an adjustable fuzzy sub-space was designed by uniform design,has been established and used in fed-batch yeast fermentationas an example.A brand-new optimization sub-network with special structure has been built andgenetic algorithm,guaranteeing the optimization in overall space,is introduced for the feed rateoptimization.On the basis of the model network,the optimal substrate concentration and theoptimal amount of fed-batch at different periods have been studied,aided with the optimizationnetwork and the genetic algorithm separately.The above results can be used as a basis for theestablishment of a fuzzy neural network controller.

Combined Application of 5% Natamycin and 0.2% Fluconazole for the Treatment of Fungal Keratitis

Purpose: To observe the clinical efficacy of combined use of 5% natamycin and 0.2% fluconazole for the treatment of fungal keratitis. Methods:A total of 65 cases diagnosed with fungal keratitis by direct smear and/or fungus culture from January 2010 to January 2013 were enrolled in this study.The duration from the onset of symptoms to admission to our ophthalmic center ranged from 9 to 90 d (mean 29.5 ±19.1 d) in the severe group, which significantly differed from the 7 to 36 d (mean 16.6±7.1 d) in the non-severe group (P<0.01). All cases were divided into non-severe and severe groups based on the degree of corneal inflammation. All cases were treated with topical use of 5% natamycin and 0.2% fluconazole once per hour. The same clinical and examination protocols were adopted for both groups. Results:In the non-severe group,23 of the 24 patients (95.8%) were healed, and 1 (4.2%) showed treatment effica cy. In the severe group,12 of 41 patients (29.3%) were healed, 11(26.8%) showed clinical efficacy, and 18(43.9%) showed no efficacy. The patients between two groups significantly differed in terms of efficacy (P<0.01). Conclusion:Combined use of 5% natamycin and 0.2% fluconazole is efficacious in treating fungal keratitis, especially mild or moderate infections.

NonliNonlinear GPC with In-place Trained RLS-SVM Model for DOC Control in a Fed-batch Bioreactor

In this study, Saccharomyces cerevisiae (baker's yeast) was produced in a fed-batch bioreactor at the optimal dissolved oxygen concentration (DOC) and growth medium temperature. However, it is very difficult to control the DOC using conventional controllers because of the poorly understood and constantly changing dynamics of the bioprocess. A generalized predictive controller (GPC) based on a nonlinear autoregressive integrated moving average exogenous (NARIMAX) model is presented to stabilize the DOC by manipulation of air flow rate. The NARIMAX model is built by an improved recursive least-squares support vector machine, which is trained by an in-place computation scheme and avoids the computation of the inverse of a large matrix and memory reallocation. The proposed nonlinear GPC algorithm requires little preliminary knowledge of the fermentation process, and directly obtains the nonlinear model in matrix form by using iterative multiple modeling instead of linearization at each sampling period. By application of an on-line bioreactor control, experimental results demonstrate the robustness, effectiveness and advantages of the new controller.

On-line Scheduling Algorithm for Penicillin Fed-batch Fermentation

An on-line scheduling algorithm to maximize gross profit of penicillin fed-batch fermentation is proposed. According to the on-line classification method, fed-batch fermentation batches are classified into three categories. Using the scheduling strategy, the optimal termination sequence of batches is obtained. Pseudo on-line simulations for testing the proposed algorithm with the data from industrial scale penicillin fermentation are carried out.

Remote Control of Fed-Batch Fermentation Systems

Bioreactor operation requires continuous monitoring of fermentation parameters and real-time control over bioreactor devices. Remote monitoring and control of the bioreactor＇s computer via the Internet avoids the necessity of personnel being continually onsite during operation. A two liter Sartorius-stedim Biostat~ A Plus fermentation system was networked and interfaced with the commercial software from GoToMyPC to allow remote control of the fermentation system utilizing the internet. The fermentation vessel was equipped with hardware calibrated for monitoring and controlling culture parameters during experimentations. The uniform resource locator controlled night-vision web camera allowed continuous monitoring of the glass fermentation vessel during the day and at night. The main window screen of the laboratory computer can be securely accessed from any portable device （i.e. laptop） capable of establishing an Internet connection and executing the commercial software from GoToMyPC. The secured internet protocol address, provided by GoToMyPC, assures that the system can only be controlled by authorized users who have been given access to the account. This interface permits the remote control of the Biostat A Plus fermentation system and possibly other automated or potentially automated culturing systems at the convenience of the user（s）.