Identification and functional properties of dominant lactic acid bacteria isolated from Kahudi, a traditional rapeseed fermented food product of Assam, India

Kahudi or Pani tenga is a very unique fermented mustard product of Assam that is prepared by mixing coarsely ground mustard with extracts of acidic Garcinia pedunculata (Thekera) or tamarind. Kahudi is produced through a spontaneous and uncontrolled solid state fermentation and very little scientific effort has been directed to understand its microflora and their functional properties. In this paper, we report the microbial flora and their dynamics during Kahudi fermentation with special emphasis on lactic acid bacteria (LAB). LAB were found to be dominant (8 log CFU/g) over other microbial flora (4 log CFU/g) during the fermentation process leading to Kahudi formation. The microbial load in Kahudi did not include any mycelial molds or pathogenic enteric bacteria. Combination of phenotypic parameters, biochemical tests, and 16S rDNA gene sequencing revealed the dominant group of LAB as Enterococcus durans, Lactobacillus plantarum, Lactobacillus fermentum, and Lactobacillus casei. The sugar fermentation and enzyme profile analysis revealed the ability of the microbial consortia to metabolize an array of indigestible sugars including D-mannose, mannitol, sorbitol, methyl-α-D-mannopyranoside, methyl-α-D-glucopyranoside, N-acetylglucosamine, amygdalin, and arbutin. Although the isolates showed good acid phosphatase activity they had weak extracellular phytase activity. This is the first report on the microbial dynamics and involvement of LAB during Kahudi fermentation

Natural pigment betacyanin as tracking dye for gel electrophoresis

Several dyes including bromophenol blue are used as tracking dye in gel electrophoresis. The stability of betacyanin extracted from spinach vine fruit (Basella rubra L.) was studied in relation to degradative factors such as pH ranging from 2 to 12 and at 100ºC. Betacyanin pigment was found to be stable at pH range 3-8 while the stability of the pigment at high temperature was found to be moderate. The effectiveness of betacyanin as a tracking dye was checked along with the bromophenol blue for agarose gel electrophoresis. The present study revealed that betacyanin from spinach fruit can be a potential alternative to conventional dye like bromophenol blue used in the loading dye preparation for agarose gel electrophoresis

Natural pigment betacyanin as tracking dye for gel electrophoresis

23-26Several dyes including bromophenol blue are used as tracking dye in gel electrophoresis. The<span style="mso-ansi-language: EN-IN;mso-fareast-language:EN-IN"> stability of betacyanin extracted from spinach vine fruit (Basella rubra L.) was studied in relation to degradative factors such as pH ranging from 2 to 12 and at 100ºC. Betacyanin pigment was found to be stable at pH range 3-8 while the stability of the pigment at high temperature was found to be moderate. The effectiveness of betacyanin as a tracking dye was checked along with the bromophenol blue for agarose gel electrophoresis. The present study revealed that betacyanin from spinach fruit can be a potential alternative to conventional dye like bromophenol blue used in the loading dye preparation for agarose gel electrophoresis. </span

Lipopeptide mediated biocontrol activity of endophytic Bacillus subtilis against fungal phytopathogens

Abstract Background The use of chemical fungicides against fungal pathogens adversely affects soil and plant health thereby resulting in overall environmental hazards. Therefore, biological source for obtaining antifungal agents is considered as an environment-friendly alternative for controlling fungal pathogens. Results In this study, seven endophytic bacteria were isolated from sugarcane leaves and screened for its antifungal activity against 10 fungal isolates belonging to the genera Alternaria, Cochliobolus, Curvularia, Fusarium, Neodeightonia, Phomopsis and Saccharicola isolated from diseased leaves of sugarcane. Among the seven bacterial isolates, SCB-1 showed potent antagonistic activity against the tested fungi. Based on the phenotypic data, Fatty Acid Methyl Esters (FAME) and 16S rRNA gene sequence analysis, the isolate SCB-1 was identified as Bacillus subtilis. The bacterial isolate was screened negative for chitinase production; however, chloroform and methanol extracts of the bacterial culture caused significant inhibition in the growth of the fungal isolates on semisolid media. Volatile component assay showed highest inhibitory activity against Saccharicola bicolor (SC1.4). A PCR based study detected the presence of the genes involved in biosynthesis of surfactin, bacillaene, difficidin, macrolactins and fengycin. Mass spectrometric analysis of the bacterial extract detected the presence of antifungal lipopeptide surfactin, but other metabolites were not detected. The biocontrol activity of the bacterial isolate was established when bacterial pretreated mung bean seeds were able to resist Fusarium infection, however, the untreated seeds failed to germinate. Conclusion The antifungal potential of isolate Bacillus subtilis SCB-1 was established against taxonomically diverse fungal pathogens including the genera Saccharicola, Cochliobolus, Alternaria and Fusarium. The potent antifungal compound surfactin as well as volatiles produced by the bacterial isolate could be responsible for its bio-control activity against fungal infections

Nutritional Properties, Antioxidant and Antihaemolytic Activities of the Dry Fruiting Bodies of Wild Edible Mushrooms Consumed by Ethnic Communities of Northeast India

A variety of cultivated mushrooms in Northeast India are well known for their taste, nutritional and medicinal benefits. Many wild-growing mushrooms are also consumed due to their exotic flavours and tastes; however, the scientific exploration of their nutritional and bioactive properties is still negligible. In the present study, the 32 wild edible mushroom samples of 11 species collected from different parts of Northeast India were evaluated for their proximate composition, mineral and vitamin (ascorbic acid and riboflavin) contents, antioxidant and antihaemolytic activity, and profiles of organic and phenolic acids. Lentinus sajor-caju and Lentinus squarrosulus had the highest carbohydrate content (49.80 g/100 g dry weight (d.w.) and 46.36 g/100 g d.w., respectively), crude protein content (20.72 g/100 g d.w. and 20.54 g/100 g d.w., respectively) and a considerable content of minerals. The highest fat content was determined in Lentinus velutinus (7.17 g/100 g d.w.). Among the minerals, potassium was found as the most abundant in all the samples. The extracts of L. sajor-caju, L. squarrosulus, and Pleurotus pulmonarius were characterized by the highest antioxidant activity, while these of L. sajor-caju, Pleurotus ostreatus, P. pulmonarius and Agaricus bisporus showed the highest antihaemolytic potential. The HPLC analysis allowed determining the high contents of ascorbic acid and a few organic and phenolic acids such as lactic acid, gallic acid, 3,4-dihydroxybenzoic acid and trans-cinnamic acid in the tested mushrooms. Other compounds viz. citric acid, caffeic acid, riboflavin, vanillic acid, pyruvic acid, and p-coumaric acid were detected with variations. This study established the nutritional and health-promoting benefits of wild edible mushrooms of Northeast India region for consumption as functional foods in human diet

Fungal interactions induce changes in hyphal morphology and enzyme production

In nature, species interacts/competes with one other within their surrounding for food and space and the type of interactions are unique to each species. The interacting partners secrete different metabolites, which may have high importance in human welfare. Fungal–fungal interactions are complex mechanisms that need better understanding. Here, 14 fungal isolates were facilitated in 105 possible combinations to interact on potato dextrose agar. Morphologically, no changes were observed when the same fungal isolates were allowed to interact within them. However, 10 interactions between different fungal isolates showed mutual replacement with each fungus; capturing territory from the other. Contrastingly, 35 interactions resulted into complete replacement as one of the fungi was inhibited by rapid growth of the other fungus. In 46 interactions, formation of barrage was observed leading to deadlock type of interaction wherein both fungi have restricted growth. To study in details about the barrage formation, two fungal interactions were taken (i) T. coccinea vs. L. lactinea and (ii) T. coccinea vs. T. versicolor. Microscopic changes in the hyphal growth during interaction were observed. There was significant increase in the enzymatic activities including cellulase, xylanase and chitinase during in-vitro fungal–fungal interaction, suggesting the importance of such interactions for commercial enzyme production