A Novel Prototype Biosensor Array Electrode System for Detecting the Bacterial Pathogen Salmonella typhimurium.

Salmonellosis caused by Salmonella sp. has long been reported all over the world. Despite the availability of various diagnostic methods, easy and effective detection systems are still required. This report describes a dialysis membrane electrode interface disc with immobilized specific antibodies to capture antigenic Salmonella cells. The interaction of a specific Salmonella antigen with a mouse anti-Salmonella monoclonal antibody complexed to rabbit anti-mouse secondary antibody conjugated with HRP and the substrate o-aminophenol resulted in a response signal output current measured using two electrode systems (cadmium reference electrode and glassy carbon working electrode) and an agilent HP34401A 6.5 digital multimeter without a potentiostat or applied potential input. A maximum response signal output current was recorded for various concentrations of Salmonella viz., 3, 30, 300, 3000, 30,000 and 300,000 cells. The biosensor has a detection limit of three cells, which is very sensitive when compared with other detection sensors. Little non-specific response was observed using Streptococcus, Vibrio, and Pseudomonas sp. The maximum response signal output current for a dialysis membrane electrode interface disc was greater than that for gelatin, collagen, and agarose. The device and technique have a range of biological applications. This novel detection system has great potential for future development and application in surveillance for microbial pathogens.

Recent developments in biorefining of macroalgae metabolites and their industrial applications - A circular economy approach.

The macroalgal industry is expanding, and the quest for novel ingredients to improve and develop innovative products is crucial. Consumers are increasingly looking for natural-derived ingredients in cosmetic products that have been proven to be effective and safe. Macroalgae-derived compounds have growing popularity in skincare products as they are natural, abundant, biocompatible, and renewable. Due to their high biomass yields, rapid growth rates, and cultivation process, they are gaining widespread recognition as potentially sustainable resources better suited for biorefinery processes. This review demonstrates macroalgae metabolites and their industrial applications in moisturizers, anti-aging, skin whitening, hair, and oral care products. These chemicals can be obtained in combination with energy products to increase the value of macroalgae from an industrial perspective with a zero-waste approach by linking multiple refineries. The key challenges, bottlenecks, and future perspectives in the operation and outlook of macroalgal biorefineries were also discussed.

Recent advances in lignocellulosic biomass for biofuels and value-added bioproducts - A critical review.

Lignocellulosic biomass is a highly renewable, economical, and carbon-neutral feedstock containing sugar-rich moieties that can be processed to produce second-generation biofuels and bio-sourced compounds. However, due to their heterogeneous multi-scale structure, the lignocellulosic materials have major limitations to valorization and exhibit recalcitrance to saccharification or hydrolysis by enzymes. In this context, this review focuses on the latest methods available and state-of-the-art technologies in the pretreatment of lignocellulosic biomass, which aids the disintegration of the complex materials into monomeric units. In addition, this review deals with the genetic engineering techniques to develop advanced strategies for fermentation processes or microbial cell factories to generate desired products in native or modified hosts. Further, it also intends to bridge the gap in developing various economically feasible lignocellulosic products and chemicals using biorefining technologies.

Characterization of thermostable serine alkaline protease from an alkaliphilic strain Bacillus pumilus MCAS8 and its applications.

This study describes the characterization and optimization of medium components for an extracellular detergent, surfactant, organic solvent and thermostable serine alkaline protease produced by alkaliphilic Bacillus pumilus MCAS8 strain isolated from Pulicat lake sediments, Tamil Nadu, India. The strain yielded maximum protease (2,214 U/ml) under optimized conditions: carbon source, citric acid-1.5 % (w/w); inducer, soyabean meal-2 % (w/w); pH 11.0; shaking condition 37 °C for 48 h. The enzyme had pH and temperature optima of 9.0 and 60 °C, respectively. The enzyme displayed the molecular mass of 36 kDa in sodium dodecyl sulphate-polyacrylamide gel electrophoresis study and exhibited activity at a wide range of pH (6.0-11.0) and thermostability (20-70 °C). More than 70 % residual activity was observed when the enzyme was incubated with dithiothreitol, ethylenediaminetetraacetic acid, ethylene glycol tetraacetic acid and H(2)O(2) for 30 min. The protease activity was also enhanced by divalent cations such as Ba(2+), Ca(2+) and Mg(2+) and was strongly inhibited by Fe(2+), Zn(2+), Sr(2+), Hg(2+) and urea. The enzyme retained more than 50 % of its initial activity after pre-incubation for 1 h in the presence of 5 % (v/v) organic solvents such as dimethyl sulphoxide and acetone. The protease could hydrolyse various native proteinaceous substrates (1 % w/v) such as bovine serum albumin, casein, skim milk, gelatine, azocasein and haemoglobin. Wash performance analysis of enzyme revealed that it could effectively remove blood stains from the cotton fabric, thus making it suitable to use as an effective detergent additive. The protease enzyme also exhibited promising result in the dehairing of goat skin. The potency of the eco-friendly enzyme without using any chemicals against washing and dehairing showed that the enzyme could be used for various industrial applications.

Evaluation of pink-pigmented facultative methylotrophic bacteria for phosphate solubilization.

Thirteen pink-pigmented facultative methylotrophic (PPFM) strains isolated from Adyar and Cooum rivers in Chennai and forest soil samples in Tamil Nadu, India, along with Methylobacterium extorquens, M. organophilum, M. gregans, and M. komagatae were screened for phosphate solubilization in plates. P-solubilization index of the PPFMs grown on NBRIP-BPB plates for 7 days ranged from 1.1 to 2.7. The growth of PPFMs in tricalcium phosphate amended media was found directly proportional to the glucose concentration. Higher phosphate solubilization was observed in four strains MSF 32 (415 mg l(-l)), MDW 80 (301 mg l(-l)), M. komagatae (279 mg l(-l)), and MSF 34 (202 mg l(-l)), after 7 days of incubation. A drop in the media pH from 6.6 to 3.4 was associated with an increase in titratable acidity. Acid phosphatase activity was more pronounced in the culture filtrate than alkaline phosphatase activity. Adherence of phosphate to densely grown bacterial surface was observed under scanning electron microscope after 7-day-old cultures. Biochemical characterization and screening for methanol dehydrogenase gene (mxaF) confirmed the strains as methylotrophs. The mxaF gene sequence from MSF 32 clustered towards M. lusitanum sp. with 99% similarity. This study forms the first detailed report on phosphate solubilization by the PPFMs.

Cellulase production by pink pigmented facultative methylotrophic strains (PPFMs).

Pink pigmented facultative methylotrophs (PPFM) isolated from water samples of Cooum and Adyar rivers in Chennai and soil samples of forests located in various districts of Tamil Nadu, India were screened for cellulase production using carboxymethylcellulose agar (CMC agar) medium. The strains showed wide variations in the production of clearing zones around the colonies on CMC agar medium flooded with Congo red. CMCase and filter paper assays were used to quantitatively measure the cellulase activity of 13 PPFM strains. Among the strains, Methylobacterium gregans, MNW 60, MHW 109, MSF 34, and MSF 40 showed cellulolytic activity ranging from 0.73 to 1.16 U mL(-1) with wide temperature (35-65°C) and pH (5 to 8) tolerance. SDS-PAGE analysis of the crude enzyme of PPFM strain MNW 60 exhibited several protein bands, and zymogram analysis revealed two dimeric cellulase bands with molecular mass of ~92 and 42 kDa. Scanning electron microscopic studies revealed significant morphological differences between the cells grown in normal and CMC amended medium. The strain MNW 60 was identified as Methylobacterium sp. based on biochemical, physiological, and morphological analyses, and the methylotrophic nature was authenticated by the presence of mxaF gene, encoding methanol dehydrogenase as a key indicator enzyme of methylotrophs, with 99% similarity to Methylobacterium lusitanum. With the 16S ribosomal RNA sequence showing 97% similarity to M. lusitanum strain MP2, this can be proposed as a novel taxon of the genus Methylobacterium. The study forms the first detailed report on the extracellular cellulase production by pink pigmented Methylobacterium sp., and it is expected that this might be the basis for further studies on cellulase production by PPFMs to explore the molecular mechanism, strain improvement, and large-scale cellulase production for its application.