THE PREBIOTIC INFLUENCE OF INULIN ON GROWTH RATE AND ANTIBIOTIC SENSITIVITY OF LACTOBACILLUS CASEI

Objective: This research study is focused on the prebiotic effect of inulin on the antibiotic sensitivity of Lactobacillus casei and on the determination of functionality of specific growth rate (µ) of the probiotic bacteria on the concentrations of lactose (CL = 10-30 g/l) and inulin (CI = 0.164-0.625 g/l) along with the optimization of growth condition through Response Surface Methodology (RSM).Methods: The sensitivity of Lactobacillus casei towards norfloxacin was determined using well diffusion method. Using the initial values of µ (h-1) of Lactobacillus casei at different values of CL (g/l) and CI (g/l), the functionality of µ on the concentrations of the carbon sources have been derived, and the optimum condition has been identified.Results: Although Lactobacillus casei is sensitive to norfloxacin, resistance is developed in the presence of inulin. Quadratic model equation µ = 0.83+0.054*CL-0.035*CI-0.049*CL*CI-0.29*CL2-0.33*CI2 is valid and the optimum value of specific growth rate is 0.8285 h-1 at CL = 20 g/l and CI = 0.32 g/l.Conclusion: The interesting observation of the development of antibiotic resistance of Lactobacillus casei in the presence of inulin suggests that the intake of probiotic Lactobacillus casei, may be done along with prebiotic inulin when a patient is treated with antibiotics like norfloxacin. Moreover, the model equation correlating the functionality of growth rate of Lactobacillus casei on lactose and inulin will be helpful in fortifying the probiotic milk products and drugs with prebiotics like inulin.Keywords: Lactobacillus casei, Prebiotic, Inulin, Antibiotic sensitivity, Statistical growth model, Optimization of specific growth rate, Response Surface Methodolog

Production of β-galactosidase in a Batch Bioreactor Using Whey through Microbial Route – Characterization of Isolate and Reactor Model

Whey was used as a source of isolation of bacterial strains, symbolized as, IB1, IB2 and IB3, capable of synthesizing β-galactosidase. The microbe labeled as IB1 was tested to be most tolerant against pH and temperature shocks, as well as, heavy metals. Subsequently, IB1 was identified as Bacillus safensis (JUCHE 1) by genetic information. In a later exercise, it was used for β-galactosidase production using whey through fermentative route. The initial concentration of substrate, i.e., lactose in microbial growth medium was varied ranging from of 5-50 g/L. It was found that the classical Monod kinetics and substrate inhibited Monod kinetics are able to describe the microbial growth kinetics at low (5-20 g/L), and high (>20 g/L) concentration ranges of lactose in growth medium respectively. Kinetics of β-galactosidase production followed the Monod incorporated modified Luedeking-Piret model and the Monod incorporated Luedeking-Piret model with substrate inhibition in the low, and high ranges of lactose concentration in growth medium respectively

SUSTAINABILITY OF THE PROBIOTIC LACTOBACILLUS CASEI IN FORTIFIED INDIAN MILK CAKES UNDER DIFFERENT PRESERVATION CONDITIONS-EFFECTS OF CO-IMMOBILIZATION OF L. CASEI AND COMMERCIAL PREBIOTIC INULIN (CHICORY BASED) AND MILLET INULIN

Objective: The objective of the present article is to identify the most suitable Indian millet inulin for the growth of probiotic Lactobacillus casei and to evaluate the effects of the fortification vectors (probiotics and probiotic-prebiotic combination in immobilized conditions) and immobilization methods on the sustainability of L. casei in a fortified Indian sweet (milk cake) preserved under different conditions.Methods: Inulin was extracted from pearl, finger and great millets. The concentrations of L. casei, grown on three millet inulins, were compared in 24 h batch culture. The L. casei and probiotic-prebiotic combinations namely L. casei-commercial inulin and L. casei-pearl millet inulin were immobilized using entrapment, external and internal microencapsulation methods. The Indian milk cake samples were fortified with the immobilized probiotic cells, co-immobilized probiotic-prebiotic combinations. The fortified samples were preserved at different conditions (temperature: 4 °C and-20 °C; Time: 1-4 w). The sustainability of L. casei in the preserved samples was determined using spread plate method and the cell concentrations were compared among all fortified samples.Results: Pearl millet inulin is determined to be the most suitable millet inulin for the growth of L. casei. The synergistic combination of L. casei–pearl millet inulin, co-immobilized with internal gelation technique is the best fortification vector for the viability of L. casei in preserved food samples.Conclusion: The L. casei, co-immobilized with pearl millet inulin through internal gelation technique, can be utilized as an effective fortification vector for the sustainability of probiotic cells in preserved Indian milk cakes and similar food samples

PREBIOTIC INFLUENCE OF PLANTAGO OVATA ON FREE AND MICROENCAPSULATED L. CASEI–GROWTH KINETICS, ANTIMICROBIAL ACTIVITY AND MICROCAPSULES STABILITY

Objective: To study the enhancement of antimicrobial effects of probiotic Lactobacillus casei (L. casei) both in free and immobilized form and in the presence of a natural prebiotic-Psyllium seed husk.Methods: Arabinoxylan was isolated from Psyllium seed husk. The isolated arabinoxylan was characterized using FTIR, TLC and HPTLC method. The growth kinetics of L. casei has been studied with and without arabinoxylan extracted from Psyllium husk. The antimicrobial activity of L. casei against Escherichia coli has been determined using glucose and arabinoxylan as substrates. Zone of inhibition in the presence of arabinoxylan has been observed. The probiotic has been immobilized through microencapsulation technique and the size distribution of the microcapsules has been microscopically determined. Effects of centrifugal force and high temperature stress on the stability of microcapsules have been studied.Results: The values of kinetic parameters, µmax and ks have been determined to be 0.379/h, 0.3942 g/l and 0.08127/h, 0.3094 g/l for glucose in MMRS and Basal media respectively. In the case of arabinoxylan the zone of inhibition was 14.5 mm and for glucose it was observed 13 mm. 15 g of microcapsules have been obtained from 5 ml of cellular broth. The size of microcapsules was in the range of 0.1 mm-0.55 mm in which 0.25 mm of diameter were maximum size.Conclusion: The presence of arabinoxylan enhances the growth and antimicrobial activity of L. casei both in free and immobilized forms. The retention of probiotic cells in fortified milk under freezing condition increases in presence of arabinoxylan. The size of microcapsules follows a normal distribution

STUDIES ON PREBIOTIC FOOD ADDITIVE (INULIN) IN INDIAN DIETARY FIBRE SOURCES - GARLIC (ALLIUM SATIVUM), WHEAT (TRITICUM SPP.), OAT (AVENA SATIVA) AND DALIA (BULGUR)

Objective: In the present investigation inulin has been extracted from dietary fibre rich Indian food stuffs, namely, garlic, wheat, oat and dalia. Inulin in the raw food stuff and in the extract has been assessed qualitatively and quantitatively. Methods: Inulin has been extracted from each food source using a combination of lab-scale chemical processes and unit operations. Qualitative assessment of inulin in different food samples and their extracts has been done using FTIR and TLC and quantitative assessment has been done using high performance liquid chromatography (HPLC) and also through combination of TLC and spectro-photometry. Results: The concentration (on dry weight basis) of inulin in natural prebiotic sources has been determined to be 16.60%, 13.07%, 8.94%, 14.95% for garlic, wheat, oat and dalia respectively. The extraction of inulin from garlic, wheat, oat and dalia was possible up to the extent of 99.46%, 77.94%, 53.31% and 89.15% respectively. Conclusion:  It may be concluded that all the food samples, investigated under the study, may serve as potential sources for extraction of prebiotic inulin. The present extraction procedure may be escalated to commercial scale for the production of inulin particularly from garlic for which the efficiency is as high as 99.46%