Review Article

Principles of Glycerol-Based Polyhydroxyalkanoate Production

Martin Koller, Lukas Marsalek

Applied Food Biotechnology, Vol. 2 No. 4 (2015), 7 Mehr 2015, Page 3-10

The article addresses the contemporary quest for inexpensive carbon feedstocks to be used for cost efficient biomediated polymer production; such polymers can potentially be applied in the food technology sector, mainly for packaging purposes. In particular, the work shines a light on crude glycerol, a surplus stream of the globally tremendously emerging biodiesel industry. Crude glycerol can be upgraded to a convenient substrate for microbial polyhydroxyalkanoate production without interfering with food- or feed production. The article covers the challenges of using crude glycerol as a feedstock in biotechnology, and gives an insight into the metabolic background of glycerol-based polyhydroxyalkanoate production. Particularities of glycerol-based polyhydroxyalkanoate biosynthesis, such as the characteristic formation of low-molecular mass polyesters, and the resulting impact on polymer processing, are also discussed in this review.

Inhibition Effect of Lactic Acid Bacteria against Food Born Pathogen, Listeria monocytogenes

Rouha Kasra-Kermanshahi, Elahe Mobarak-Qamsari

Applied Food Biotechnology, Vol. 2 No. 4 (2015), 7 Mehr 2015, Page 11-19

In recent years due to changes in lifestyle and eating behavior of the human populations, disease caused by contaminated food has increased significantly. Listeria monocytogenes, Escherichia coli O157:H7 and Salmonella enteric are three of the most important food borne bacterial pathogens and can lead to food borne diseases. Also today wide spread of resistance to antibiotics among bacteria occurs due to increased consumption of antibiotics. Therefore, there is a dire need for development of new types of safe antimicrobial compounds. In this field, the most extensive research and commercial practices are based on probiotic bacteria. Probiotics, specifically lactic acid bacteria, are broadly used in the food industry for fermentation. Furthermore, probiotics produce valuable antimicrobial products that results to health effects. Now, the use of probiotic for treatment of disease is thought to be an effective way to improve the gut health and an alternative for treatment by antibiotics. Probiotics contribute to food safety by inhibition of the growth of other bacteria. Lactic acid bacteria can be used as protective cultures to compete with several pathogens and undesired organisms. Since food safety has become a significant international concern, here we investigated application of lactic acid bacteria for controlling the growth of Listeria monocytogenes.

Original Article

Optimization of Monacolin Production in a Controlled System

Shafieh Mansoori, Fatemeh Yazdian, Majid Azizi, Mojgan Sheikhpour, Gassem Amoabediny, Javad Hamedi, Behnam Rasekh

Applied Food Biotechnology, Vol. 2 No. 4 (2015), 7 Mehr 2015, Page 21-26

Monascus purpureus is a fungus that had been cultured on the rice in eastern Asian countries since thousands years ago and used as a food for long years. The fungus produces very valuable metabolites with polyketide structure. The most important metabolite is Monacolin K, lovastatin or competitive inhibitor of 3-Hydroxy-3-Methylglutaryl-Coenzyme A reductase (an affective enzyme in cholesterol synthesis). This metabolite has various properties including reducing blood cholesterol, preventing infection, and treatment of progressive renal disease, a variety of tumors, vascular diseases and bone fractures. In this study, Monascus purpureus PTCC5303 has been used for lovastatin production in liquid fermentation. The nutritional concentrations that were significant in biomass and lovastatin production including maltose and MgSO4 were optimized by Response Surface Methodology in a mili-bioreactor. The optimum concentration of maltose and MgSO4 was obtained as 10 g l-1 and 0.78 g l-1, respectively. According to our results, maximum lovastatin production under optimum conditions including maltose 10 g l-1, peptone 5 g l-1, MgSO4.7H2O 0.78 g l-1, MnSO4.H2O 0.5 gl-1, KH2PO4 4 g l-1, thiamine 0.1 g l-1, and pH=7 at 30 °C, 130 rpm and flow rate 1.8 l min-1 was obtained to be 309 μg l-1 after 10 days of fermentation period.

Microencapsulation and Fermentation of Lactobacillus acidophilus LA-5 and Bifidobacterium BB-12

Maryam Yari, Jamshid Fooladi, Mohammad Ali Kargar Motlagh

Applied Food Biotechnology, Vol. 2 No. 4 (2015), 7 Mehr 2015, Page 27-32

Because of poor survival of probiotic bacteria, microencapsulation evolved from the immobilized cell culture technology used in the biotechnological industry. Two probiotic strains, Bifidobacterium (BB-12) and Lactobacillus acidophilus (LA-5) were immobilized in calcium alginate by extrusion method. Encapsulation parameters and efficacy of this method were evaluated. Growth factors of these two bacteria were also measured by culturing in 10-L fermenter. Growth curves were obtained with respect to optical density and dry biomass weight. Encapsulation yield was over than 60% in each experiment. Scanning electron microscopy (SEM) of Entrapment of cells in alginate matrix and cross-sections of dried bead were obtained and illustrated. Bifidobacterium have been shown better biotechnological properties.

Effects of Salicylic Acid on Carotenoids and Antioxidant Activity of Saffron (Crocus sativus L.)

Somayeh Tajik, Fatemeh zarinkamar, Vahid Niknam

Applied Food Biotechnology, Vol. 2 No. 4 (2015), 7 Mehr 2015, Page 33-37

Saffron (Crocus sativus L.), the most valuable medicinal food product, belongs to the Iridaceae family, which has been widely used as a coloring and flavoring agent. The stigmas contain three major compounds; crocins (carotenoid compound responsible for color), picrocrocin (responsible for taste) and safranal (responsible for odor). It has been used for medicinal purposes, as a spice and condiment for food and as a dye since ancient times. Numerous studies have shown crocins as main carotenoids of saffron to be capable of a variety of pharmacological effects, such as protection against cardiovascular diseases and inhibition of cancer cell development. Salicylic acid is a signaling molecule and a hormone-like substance that plays an important role in the plant physiological processes. Due to the importance of saffron as a valuable product, the aim of this study is to investigate the effect of salicylic acid application (0.01, 0.1 and 1 mM) on crocin and safranal content and antioxidant activity of stigmas. The results showed that salicylic acid application at 1 mM was the most effective treatment in increasing the crocin content and stronger antioxidant activity of stigmas, but it had a negative effect on safranal content; the highest quantity of this compound was observed in the control plants.

The potential of bulk starter fermentation strategy for production of a cost-effective and safe source of β-galactosidase was investigated. Three different bulk starter media with different compositions were selected, and an industrial yogurt starter culture strain, L. bulgaricus DSM 20081 was cultivated in these media under pH-controlled conditions (pH=5.6) at 43°C. The media consisted of 1) bulk starter medium based on skim milk and whey, 2) bulk starter medium based on whey, and 3) reconstituted skim milk. The kinetic parameters of growth and β-lactic acid production were estimated using the experimental data with the Garcia and Luedeking-Piret models, respectively. β-galactosidase production kinetics was also simulated using appropriate models based on biomass and lactic acid production. Growth in the bulk starter medium based on skim milk and whey resulted in a higher rate of lactic acid production (7.35 ± 0.23 mg lactic acid ml-1 media h-1) and β-galactosidase activity (800.1± 0.7 nmol ONP ml-1 media) compared to other two media (P<0.01). Simulation of β-galactosidase production based on the rate of lactic acid production resulted in a very good agreement with the experimental data of all three tested media. The results revealed the potential of bulk starter fermentation strategy and skim milk + whey based medium for in-house and relatively low cost production of food-grade β-galactosidase by dairy plants.

Substrates' concentration profile was studied in a porous matrix containing immobilized amyloglucosidase for glucose production. This analysis was performed by using an analytical method called Least Square Method, and the results were compared with numerical solution. Effects of effective diffusivity, Michael's constant, maximum reaction rate and initial substrate concentration were studied on Soluble Starch and Dextrin concentration in the spherical support. The outcomes revealed that Least Square Method has an excellent agreement with numerical solution, and in the center of support, substrate concentration is minimum. Increasing of effective diffusivity and Michael's constant reduced the Soluble Starch and Dextrin profile gradient.