Rathinam Raja

Mechanism of action of probiotics

ABSTRACT The modern diet doesn’t provide the required amount of beneficial bacteria. Maintenance of a proper microbial ecology in the host is the main criteria to be met for a healthy growth. Probiotics are one such alternative that are supplemented to the host where by and large species of Lactobacillus, Bifidobacterium and Saccharomyces are considered as main probiotics. The field of probiotics has made stupendous strides though there is no major break through in the identification of their mechanism of action. They exert their activity primarily by strengthening the intestinal barrier and immunomodulation. The main objective of the study was to provide a deep insight into the effect of probiotics against the diseases, their applications and proposed mechanism of action. Key words: Anti-allergic, Gastrointestinal problems, Immunomodulation, Infectious diseases, Probiotics * Author for correspondence: rraja307@yahoo.co.in INTRODUCTION The gut microenvironment has an effect on the nutrition, feed conversion and disease of the host, thereby maintaining the microbial ecology of the gut (Guarner and Malagelada 2003). During the periods of stress, illness or antibiotic treatment, the gut flora is often changed in favor of harmful bacteria that may cause diarrhea and loss of appetite (Cremonini et al. 2002; Harish and Varghese 2006). Overgrowth of the harmful bacteria and its subsequent invasion of the system lead to inflammatory, immunological, neurological and endocrinological problems. Induction of the growth of beneficial bacteria is one of the possible solutions to normalize the health conditions. This could be achieved by the supplementation of viable bacterial cells into the host. Probiotics can help to build up the beneficial bacterial flora in the intestine and completely exclude the pathogenic bacteria. These bacteria also release some enzymes which help in the digestion of the feed (Jean et al. 2003). A daily intake of 10

Recent developments in therapeutic applications of Cyanobacteria

Abstract The cyanobacteria (blue-green algae) are photosynthetic prokaryotes having applications in human health with numerous biological activities and as a dietary supplement. It is used as a food supplement because of its richness in nutrients and digestibility. Many cyanobacteria (Microcystis sp, Anabaena sp, Nostoc sp, Oscillatoria sp., etc.) produce a great variety of secondary metabolites with potent biological activities. Cyanobacteria produce biologically active and chemically diverse compounds belonging to cyclic peptides, lipopeptides, fatty acid amides, alkaloids and saccharides. More than 50% of the marine cyanobacteria are potentially exploitable for extracting bioactive substances which are effective in killing cancer cells by inducing apoptotic death. Their role as anti-viral, anti-tumor, antimicrobial, anti-HIV and a food additive have also been well established. However, such products are at different stages of clinical trials and only a few compounds have reached to the market.

Biomass from Microalgae: An Overview

Microalgal biomass offers a number of advantages over conventional biomass such as higher productivities, use of non-productive land, reuse and recovery of waste nutrients, use of saline or brackish waters, and reuse of CO2 from power-plant flue-gas. The production of microalgal biomass reduces Greenhouse Gases (GHG) and provides biofuel as a replacement for fossil fuels. They are useful for production of food, health supplements, fodder, biofuel, aquaculture, fine chemicals and various biotechnological applications. The most commonly used marine algal cultures are Botryococcus braunii, Chlorella vulgaris, Chaetoceros muelleri, Dunaliella salina, Nannochloropsis oculata, Arthrospira maxima, Scenedesmus quadricauda. The current review provides details of the microalgal biomass with emphasis on strain selection, cultivation, strain improvement and biotechnological potentials.

Antioxidant activity and lipid profile of three seaweeds of Faro, Portugal

Three seaweeds, Codium fragile (Suringar) Hariot, Ulva lactuca (Linn.) members and Eisenia arborea (Areschoug) (Phaeophyta) were assessed for their antioxidant activities and lipid profile. Antioxidant activities of methanolic and aqueous extracts were analyzed for DPPH free radical scavenging, FRAP, total antioxidant, ABTS radical cation decolorizing, reducing power, total flavonoid, and total phenolic contents. Methanolic extract of E. arborea was found to contain high phenolic and flavonoid contents with higher antioxidant activities in all assays studied. Aqueous extract of E. arborea was the next active extract, whereas both the extracts of C. fragile were not highly anti-oxidative in nature. The methanolic extract of U. lactuca possessed higher activity and higher phenolic content compared to aqueous counterparts. This suggests the potential uses of seaweeds as a source for natural bioactive compounds with more antioxidant activities. Among these three seaweeds, E. arborea was found to have higher activities and their lipid and chemical constituents were identified by GCMS and LCMS.

Microalgae as an Attractive Source for Biofuel Production

With the depletion of fossil fuel resources and the limited availability of petroleum-derived transport fuel, along with the contribution to global warming, the environmental benefits of renewable biofuel are seen as the best alternative source in recent years. Among the third-generation biodiesel feed stocks such as food crops (sugarcane, sugar beet, maize and rapeseed) and non-food crops (Jatropha sp., Cassava sp., lignocellulosic materials), microalgae has been hailed as the third-generation biodiesel. Microalgae are the only fuel source that can be sustainably developed in the near future, and can produce ten times more oil than oleaginous plants. Biodiesel from microalgae has received much attention world-wide in recent years due to its carbon-neutral status. The higher neutral lipid contents of microalgae also surpass terrestrial plants for biofuel production, and microalgae are the largest biomass producers. They can accumulate high concentrations of triacylglycerol as a storage lipid under photooxidative stress and other unfavorable environmental conditions within a short period of time. This chapter provides an overview of the production of biodiesel from microalgae and includes algae cultivation, biomass production, harvesting, and downstream processing, along with a list of companies aiming to develop biodiesel from microalgae.

Comparison of integrated sustainable biodiesel and antibacterial nano silver production by microalgal and yeast isolates

Microalgal isolates (Chlorella sp. and Spirulina sp.) and yeast isolates (Candida albicans and Saccharomyces sp.) were employed as the resources of biodiesel production and silver nanoparticle synthesis. The prominent peaks of the FTIR spectrum accustomed the efficient lipid property. The developed profile containing fatty acid methyl ester (FAME) displayed the elevated amount of both saturated (C15:0, C17:0, C21:0) and unsaturated (C17:1, C18:2, C20:4) fatty acids. The physicochemical properties analyzed by using Biodiesel analyzer V1.1.software, confirmed the competency of the isolates for sustainable biodiesel production. Biosynthesis of silvernanoparticles (AgNPs) were accomplished extracellularly by using supernatant of microalgal and yeast culture. The maximum absorbance at 420 and 421 nm under UV-visible spectra showed the presence of nanoparticles. The purity of the synthesized AgNPs were analyzed by XRD analysis. The elemental silver presence was affirmed by EDAX, SEM and AFM, the results revealed spherical crystalline shaped nanoparticles of size ranging from 2.0 to 7.3 nm. The antimicrobial efficacy of the silver nanoparticles (AgNPs) against various clinical pathogens which includes Bacillus sp., E. coli, Klebsiella sp., Proteus sp. and Staphylococcus aureus were observed. However, enhanced antimicrobial activity was displayed by the AgNPs, produced by Candida albicans (12 mm) against Bacillus sp., and E.coli, the nanoparticle produced by Chlorella sp. showed the least antagonistic activity (07 mm).