Rubina Nelofer

Comparison of the estimation capabilities of response surface methodology and artificial neural network for the optimization of recombinant lipase production by E. coli BL21

Response surface methodology (RSM) and artificial neural network (ANN) were used to optimize the effect of four independent variables, viz. glucose, sodium chloride (NaCl), temperature and induction time, on lipase production by a recombinant Escherichia coli BL21. The optimization and prediction capabilities of RSM and ANN were then compared. RSM predicted the dependent variable with a good coefficient of correlation determination (R2) and adjusted R2 values for the model. Although the R2 value showed a good fit, absolute average deviation (AAD) and root mean square error (RMSE) values did not support the accuracy of the model and this was due to the inferiority in predicting the values towards the edges of the design points. On the other hand, ANN-predicted values were closer to the observed values with better R2, adjusted R2, AAD and RMSE values and this was due to the capability of predicting the values throughout the selected range of the design points. Similar to RSM, ANN could also be used to rank the effect of variables. However, ANN could not predict the interactive effect between the variables as performed by RSM. The optimum levels for glucose, NaCl, temperature and induction time predicted by RSM are 32xa0g/L, 5xa0g/L, 32°C and 2.12xa0h, and those by ANN are 25xa0g/L, 3xa0g/L, 30°C and 2xa0h, respectively. The ANN-predicted optimal levels gave higher lipase activity (55.8xa0IU/mL) as compared to RSM-predicted levels (50.2xa0IU/mL) and the predicted lipase activity was also closer to the observed data at these levels, suggesting that ANN is a better optimization method than RSM for lipase production by the recombinant strain.

Sequential optimization of production of a thermostable and organic solvent tolerant lipase by recombinant Escherichia coli

Several medium formulations were screened for the production of a thermostable and organic solvent tolerant lipase by a recombinant Escherichia coli BL21. The highest lipase production (28.9u2009±u20094.1xa0IU/mL) was obtained in Luria Bertani medium with the addition of 1% (w/v) glucose. The medium formulation and fermentation conditions were then subjected to sequential optimization. Using a Plackett-Burman design, glucose, NaCl, temperature and induction time were found to be the most significant variables affecting lipase production, and these were then optimized using response surface methodology (RSM). The large value of R2 (0.979) showed that the quadratic model used for the prediction is highly significant. The optimum levels of these four significant variables (glucose, NaCl, temperature and induction time) as predicted by RSM were 32.4xa0g/L, 5xa0g/L, 31.7°C and 2.1xa0h, respectively. The amount of lipase activity (50.2u2009±u20094.5xa0IU/mL) produced under these optimal conditions fitted well to the value (48.9xa0IU/mL) predicted by RSM. Production of lipase in optimized fermentation was about 2.5-fold higher than in non-optimized fermentation.

Enhancement of BLIS production by Pediococcus acidilactici kp10 in optimized fermentation conditions using an artificial neural network

The present study was aimed at enhancing the production of bacteriocin-like inhibitory substance (BLIS) produced by Pediococcus acidilactici Kp10 through optimizing the fermentation parameters. M17 was chosen in preliminary study as a culture medium because BLIS production was nine times higher (1427.7 AU mL−1) compared to that produced by MRS (160 AU mL−1). The fermentation parameters such as temperature, inoculum size, buffer strength, concentration of tween 80 and agitation speed were screened using two level half-factorial design. BLIS production is influenced by three most significant factors identified as temperature, inoculum size and agitation speed, which were further optimized using an artificial neural network (ANN). ANN predicted that a maximum activity of 5262.64 AU mL−1 would be obtained at optimum conditions of 120 rpm, 3% and 28.5 °C. The observed BLIS activity at the predicted optimum levels of the tested variables in ANN was 5118.5 AU mL−1, which was close to the predicted BLIS activity. Increased BLIS activity in the final solution, which resulted from the optimized process, would reduce downstream steps such as concentrating the product during purification.

Nutritional upgrading of various feed ingredients through co-culture solid state fermentation / Çeşitli yem içerikleri besin değerlerinin birlikte kültür katı hal fermentasyonu kullanılarak artırılması

Abstract Objective: The purpose of the present study was to enhance nutritional qualities of various agricultural byproducts such as wheat bran, rice bran and rice polish through co-culture solid state fermentation (SSF) using Candida utilis and Rhizopus oligosporus for their better exploitation as feed ingredients. Methods: Co-culture solid state fermentation (SSF) was carried at 30oC for 48 h by employing Candida utilis and Rhizopus oligosporus on various agricultural byproducts like wheat bran, rice bran and rice polish. After that the fermented agricultural byproducts were dried in hot air oven at 80oC and analyzed to compare with unfermented byproducts. Results: The results of the proximate analysis showed that crude protein contents increased significantly (p≤0.05) in all the fermented substrates with concurrent decrease in nitrogen free extract (NFE) contents. A significant reduction in anti nutritional content (phytic acid) was also observed in fermented products whereas values of mineral contents [calcium (Ca) and phosphorus (P)] were found high. Resultantly, high mineral contents improved Ca: P ratio in the fermented products. Shelf life study showed that the fermented substrates were nutritionally stable and no significant changes in nutritional values were observed up to 90 days. Conclusion: All these results showed that the fermented substrates are nutritionally better and can be successfully exploited as animal feed for better growth of livestock. Özet Amaç: Bu çalışmanın amacı, buğday kepeği, pirinç kepeği, pirinç kabuğu gibi çeşitli tarımsal yan ürünlerin yem içeriği olarak kullanımında Candida utilis ve Rhizopus oligosporus kullanılarak birlikte kültür katı hal fermentasyonu (SSF) ile besin değerlerinin artırılmasıdır. Metod: Birlikte kültür katı hal fermentasyonu (SSF) 30°C de 48 s Candida utilis ve Rhizopus oligosporus kullanılarak buğday kepeği, pirin kepeği, pirinç kabuğu gibi çeşitli tarımsal yan ürünler üzerinde uygulanmıştır. Daha sonra elde edilen yan ürünler üsıcak hava fırınında 80°C’de kurutulmuşlar ve fermente olmamış ürünler ile karşılaştırmak sureti ile analiz edilmişlerdir. Bulgular: Yaklaşık analiz sonuçlarına göre, ham protein içerikleri, tum fermente substratlarda istatistiksel olarak anlamlı (p≤0.05) şekilde yükselirken azot içermeyen ekstrakt (NFE) içerikleri belirgin şekilde düşmüştür. Fermente ürünlerde önemli bir anti besin bileşeni olan fitik asitin belirgin bir şekilde düştüğu gözlenirken mineral içeriklerinin (kalsiyum (Ca) ve Fosfor (P)) arttığı saptanmıştır. Sonuc olarak yüksek mineral içerikleri, fermente urünlerde Ca: P oranının iyileşmesine neden olmuştur. Raf ömrü calışmaları da fermente ürünlerin besin içeriklerinin dayanıklı olduğunu ve 90 güne kadar istatistiksel olarak anlamlı bir değişim olmadığını göstermiştir. Sonuç: Tüm bu sonuçlar fermente substratların besleyici olarak daha iyi olduğunu ve hayvan yemi olarak iyi gelişim için besi hayvanlarında başarılı bir şekilde kullanılabileceğini göstermiştir.

Process Optimization for Endoglucanase Production by in Submerged Fermentation

Muhammad Irfan, Umar Asghar, Muhammad Nadeem, Hafiz Abdullah Shakir, Javed Iqbal Qazi, Rubina Nelofer, Quratulain Syed Department of Zoology, University of the Punjab New Campus, Lahore, Pakistan. Food & Biotechnology Research Centre (FBRC), Pakistan Council of Scientific and Industrial Research (PCSIR) Laboratories Complex, Ferozepure Road, Lahore, Pakistan. Department of Zoology, University of the Punjab New Campus, Lahore, Pakistan. Food & Biotechnology Research Center, PCSIR Labs Complex, Ferozpure Road, Lahore Pakistan.

Kinetics and modelling of batch fermentation for the production of organic solvent tolerant and thermostable lipase by recombinant E. coli / Organik çözücü toleranslı ve ısıya dayanıklı rekombinan E. coli lipaz üretiminin kinetiği ve grup fermentasyonu modellemesi

Abstract Objective: Kinetics of organic solvent tolerant and thermostable lipase production by recombinant E. coli in shake flask level and 2 L stirred tank bioreactor level was studied to observe the variations of important kinetic parameters at two different levels of bioprocess. Methods: Unstructured models based on Monod equation for growth and Luedeking-Piret equation for lipase production and glucose consumption were used to predict cell growth, lipase production and glucose utilization. The shake flask fermentation experiments were carried out at different initial glucose and yeast extract concentrations using recombinant bacterial strain E. coli BL21. Lipase production was also carried out using 2L stirred tank bioreactor for comparison. Results: In all cases, the data fitted well to the proposed models. The highest growth and lipase activity were obtained at 25 g/L glucose and 25 g/L yeast extract. Cell growth (6.42 g/L) and lipase production (65.32 IU/mL) in 2 L stirred tank bioreactor was comparable to those obtained in shake flask fermentations. The calculated value of growth associated constant (9.874 IU/g/h) was much higher than that of non-growth associated constant (0.022 IU/g/h) in bioreactor as well as in shake flasks. The values of maximum specific growth rate (μm) and glucose saturation constant (KS) for shake flask fermentations, calculated from Monod equation, were 0.476 h-1 and 5.237 g/L respectively. Conclusion: From the modelling exercise, it was concluded that the lipase production is dominantly growth associated process. The kinetic parameter values for fermentations in shake flask and 2L stirred tank bioreactor were comparable, indicating that the bioprocess could be transferred into larger scale. Özet Amac: İki değişik biyoproses seviyesinde kinetik değişen parametrelerinin gozlemlenmesi amacı ile calkalama hunisi ve 2 litrelik biyo reaktor kapasitelerinde rekombinan E. coli ile organik cozucu ve ısıya dayanıklı lipaz uretimi calışılmıştır. Metod: Hucre buyumesi, lipaz uretimi ve glikoz kullanımının belirlenmesi amacı ile yapılandırılmamış modeler uzerinde buyume icin Monod denklemi, lipaz uretimi ile glikoz tuketimi icin de Luedeking - Piret denklemi kullanılmıştır. Calkalama hunisi fermentasyon deneyleri değişik glikoz ve maya eksrakt konsantrasyonlarında rekombinan E. coli BL21 bakteri suşu kullanılarak yapılmıştır. Karşılaştırma icin lipaz uretimi ayrıca 2 litrelik biyoreaktor tankı icinde de yapılmıştır. Bulgular: Her durumda veriler onerilen modellere tam olarak uymuştur. En yuksek buyume seviyesi ve lipaz aktivitesi 25 g/L glikoz ve 25 g/L maya ekstraktında elde edilmiştir. İki litrelik karıştırmalı biyo reaktorden elde edilen hucre buyumesi (6.42 g/L) ve lipaz uretimi (65.32 IU/mL), calkalamalı huni sisteminden elde edilen veriler karşılaştırılabilir olarak bulunmuştur. Biyoreaktor ve calkalama hunisi icindeki hesaplanan buyumeye dayalı sabit (9.874 IU/g/h), buyume olmayan sabite gore (0.022 IU/g/h) cok yuksek elde edilmiştir. Maksimum ozgul buyume oranı (μm) ve calkalama şişesi fermantasyonları icin Monod denklemi ile hesaplanan glukoz doyma sabiti (KS) değerleri sırasıyla 0.476 h-1 ve 5.237 g / L olarak bulunmuştur. Sonuc: Modelleme calışmasına gore lipaz uretimin baskın olarak bir buyume ilişkili surec olduğu sonucuna varılmıştır. Calkalama hunisi ve 2 litrelik karıştırmalı tank biyoreaktorunden elde edilen sonuclar karşılaştırılabilir olarak bulunduğundan bu biyoprosesin daha buyuk olcekli olarak yapılmasının mumkun olduğu sonucuna varılmıştır.