• Energy Research

Background: Phenolic compounds are food-derived bioactive compounds well-known for their antioxidant and anti-inflammatory properties. They are in the spotlight for the management of diabetes due to their positive effects on glucose homeostasis. Materials and methods: We have performed a literature review on the main topics related to the application of phenolic compounds as functional food ingredients. This includes extraction and purification from vegetable sources and agro-industrial by-products, encapsulation to improve their solubility and bioavailability, and preclinical and clinical evidence linking these compounds with anti-diabetic activity. Objectives: (1) provide an understanding of the role of phenolic compounds on diabetes; (2) identify green technologies for phenolic compounds extraction from agri-food by-products following a biorefinery scheme; (3) underline the relevance of encapsulation techniques using nanotechnology to improve their bioavailability; (4) discuss the therapeutic efficacy of polyphenols. Results: This review compiles recent relevant research on phenolic compounds extraction from renewable resources, their purification from agri-food by-products, and encapsulation strategies using eco-friendly processes. It also highlights the preclinical and clinical evidence on phenolic compounds’ antidiabetic activity, giving insight into their mechanisms of action. Conclusions: This review explores the latest advances in polyphenols and how their benefits in glucose homeostasis can be applied toward improving the health of patients with diabetes and related conditions.

Extremophiles are organisms that have evolved to exist in a variety of extreme environments. They fall into a number of different classes that include thermophiles, halophiles, acidophiles, alkalophiles, psychrophiles, and barophiles (piezophiles). Extremophiles have the potential to produce uniquely valuable biocatalysts that function under conditions in which usually the enzymes of their nonextremophilic counterparts could not. Among novel enzymes isolated from extremophilic microorganisms, hydrolases, and particularly lipases and esterases are experiencing a growing demand. Lipases (EC 3.1.1.3) and esterases (EC 3.1.1.1) catalyze the cleavage of ester bounds in aqueous media and the reverse reaction in organic solvents. Both lipolytic enzymes have relevant applications in food, dairy, detergent, biofuel, and pharmaceutical industries. Here, we summarize the properties of lipases and esterases from the main extremophile groups: thermophiles and hyperthermophiles, psychrophiles, halophiles, alkalophiles/acidophiles, and solvent-resistant microorganisms.We report the biomass and lipolytic activity production by Thermus thermophilus HB27 in 5-L stirred-tank bioreactor at 70°C. Suitability of thermal spring water for culture media formulation is shown. In addition, a protocol to isolate and purify a cell-bound esterase from this microorganism is described.

Several studies in laboratory-scale bioreactors are undertaken in order to verify the beneficial effect of thermal spring water in the culture medium of Thermus thermophilus HB27. Two bioreactor configurations, stirred tank and airlift, are investigated to determine the most suitable one to develop a continuous process. Water mineral composition affects the lipolytic enzyme secretion and growth of T. thermophilus HB27 in both bioreactor configurations. Furthermore, the lipolytic activity is strongly enhanced when stirred tank bioreactor is used. Moreover, operation in a stirred tank at an agitation rate of 650 rpm leads to the highest total lipolytic activity (intra- and extracellular enzyme) around 280 U/L after 32 h. Continuous cultures operating in the optimised conditions determined in batch cultures are carried out. It is noticeable that the stirred tank bioreactor was able to operate in a continuous flow mode without operational problems. In addition, the lipolytic activity obtained is about 2-fold higher than that attained in batch cultures.

An interesting component of Opuntia ficus-indica is the mucilage for its properties and industrial uses. However, the great variability of its quantity and quality caused by different growing conditions, the hydroponic system is an alternative. The objective of the present study was cultivating 4 species of Mexican Nopal in a hydroponic system, extract and characterize the mucilage. The characterization consists of pH, ºBrix, colour, proximal analysis, phenols, antioxidant activity, crystallinity, and chemical bonding constituents. ‘Copena F1’ is the best alternative for production of biomass and mucilage. ‘Villanueva’ had high levels of phenols (1,311.83 mg GAE g-1), antioxidant capacity ABTS·+ (6,301.12 mg TE g-1) and FRAP (536.26 mg GAE g-1). A large amount of lipids (1.39%), and nitrogen-free extract (49.27%). The functional groups of the mucilage were identified (-OH, -CH, -CH2, -CH3, C=C, HCH, -CHO) and gypsum, cellulose, SiO2 CaSO4, C2H2K2O5, CaCO3 and CaH2 by X-ray diffraction. The hydroponic system is a viable alternative for production of nopal and mucilage of high-quality mucilage that can be used in several sectors of the industry.

Thermus thermophilus HB27 produces important levels of extracellular lipolytic activity when grown for 30 h at 70 degrees C in a complex medium. A method to detect esterase activity in these samples after non-reducing SDS-polyacrylamide electrophoresis was developed. The method, that implies the renaturalisation of the enzymes in the SDS-gels by washing with Triton X-100 at high temperatures, allowed detecting three esterases with different molecular weights (108, 62 and 34 kDa, respectively). The electrophoretic mobility determined under different experimental conditions suggested that the 34- and 108 kDa-esterases might correspond with two oligomeric states of a sole enzyme (monomer and trimer). Dissociation of the trimer into the monomer started when the samples were heated at temperatures higher than 60 degrees C in the presence of sodium dodecyl sulphate. Evidences were found that indicated the independent nature of the 62 kDa-esterase. A method to purify these enzymes from postincubates of T. thermophilus HB27 was developed following three steps: sodium cholate treatment, ethanol/ether precipitation and hydrophobic chromatography. In this way, an enzyme solution was obtained that contained the identified esterases/lipases. The partially purified enzymes showed an optimum of activity for the hydrolysis of p-nitrophenyl laurate at alkaline pH values and 80 degrees C, a high thermal stability and were very stable in the presence of high concentrations of isopropanol.

AbstractBACKGROUNDThe aim of this work was to determine the most favorable conditions for the production of xylooligosaccharides (XOS) from Brazilian Syrah grape pomace. Chemical processes were performed using a rotatable central composite design where the concentration of sulfuric acid or sodium hydroxide and the grape pomace flour/solvent mass ratio were the dependent variables. Enzymatic production was also evaluated using xylanase produced by Aspergillus niger 3T5B8 and Viscozyme® enzymatic commercial cocktail.RESULTSChemical extraction allowed to recover 21.8–74.6% and 5.2–96.3% of total XOS for acidic and alkaline processes respectively. Enzymatic production extracted up to 88.68 ± 0.12% of total XOS using xylanase and up to 84.09 ± 2.40% with Viscozyme®.CONCLUSIONThe present study demonstrated different feasible methods to produce high‐added‐value molecules, i.e. XOS, from Syrah grape pomace flour, valorizing this major by‐product. The use of enzymatic cocktails demonstrated to be an alternative to the conventional methods, allowing to obtain an eco‐friendly and sustainable grape pomace extract. © 2018 Society of Chemical Industry

The production of biomass and antibacterial extracellular products by Lactobacillus casei subsp. casei CECT 4043 was followed in both batch and in realkalized fed-batch cultures. Enhanced concentrations of biomass and antibacterial extracellular products were obtained with the use of the latter fermentation technique in comparison with the batch mode. The culture obtained by fed-batch fermentation was mixed with skim milk and used to prepare a probiotic feed for weaned piglets. To test the effect of the potentially probiotic culture of L. casei on body weight gain, feed intake, feed conversion efficiency, and on fecal coliform counts of piglets, two groups of animals received either feed supplemented with the probiotic preparation or avilamycin for 28 days. The control group was fed nonsupplemented feed. At the end of the administration period (day 28), the groups receiving probiotic and avilamycin exhibited the highest average body weight gain values, although the mean feed intake and feed conversion efficiency values were not different among the groups (P > 0.05). For the entire experimental period (42 days), the control group exhibited the lowest feed intake value, the probiotic group exhibited the highest feed conversion efficiency value, and the antibiotic group exhibited the highest body weight gain (P 0.05). Fecal coliform values decreased (although not significantly) by day 28 in the three groups. However, the mean counts returned to pretreatment levels by day 42 in all groups.

The influence of initial pH on growth and nutrient (total sugars, nitrogen, and phosphorous) consumption byEnterococcus faeciumCECT 410 was studied during batch cultures in whey. With these data, two realkalized fed-batch fermentations were developed using different feeding substrates. The shift from homolactic to mixed acid fermentation, the biphasic kinetics observed for cell growth and nitrogen consumption and the increase in the concentrations of biomass and products (lactic acid, acetic acid, ethanol, and butane-2,3-diol) were the most noteworthy observations of these cultures. Modelling the fed-batch growth ofEnt. faeciumwith the Logistic and bi-Logistic models was not satisfactory. However, biomass production was best mathematically described with the use of a double Monod model, which was expressed in terms of biomass, product accumulation, and nitrogen utilization. Product formation was successfully modelled with a modified form of the Luedeking and Piret model developed in this study.