Alpha amylase is an important enzyme used in different industries, which degrades starch into smaller disaccharides. Extracellular α-amylase producing organisms were isolated from soil samples from Mauritius and identified by standard biochemical tests. In this study, the high yielding strain was used for amylase production. The potential of four readily available substrates, namely sugarcane bagasse, potato peel, kitchen wastes and banana peel to induce amylase production was investigated. Different parameters like temperature (30ºC, 40ºC, 50ºC, 60ºC & 70ºC), different pH (5.0, 6.0, 7.0, 8.0 & 9.0) and inoculum sizes (10%, 20%, 50%, 100% & 150% v/w) were used for the α-amylase production. It was found that α-amylase production and activity was highest for potato peel at 50ºC at pH 6.0 and inoculum size 50% (v/w). Amylase assays performed at different incubation temperatures (30ºC -60ºC) and pH (5-9) showed that the amylase worked best at 50ºC and pH 7.Based on results of biochemical tests and 16S ribosomal RNA gene sequences, the isolate was identified to belong to the Betaproteobacteria, closely related to Naxibacter haematophilus (99% sequence similarity to the type strain).

Purpose The marine environment harbours diverse bacterial species which can be exploited for the production of valuable compounds such as exopolysaccharides (EPS) which hold promises for biotechnological applications. The coastal waters of Mauritius is a relatively underexplored marine environment and in this study, isolated bacterial species were tested for the production of EPS exhibiting antibacterial properties against human bacterial pathogens from the genera Acinetobacter, Bacillus, Campylobacter, Enterobacter, Enterococcus, Escherichia, Proteus, Pseudomonas, Salmonella, Streptococcus and Staphylococcus. Methods Bacteria were first isolated from seawater samples. Using the disc diffusion method, their EPS were tested for antibacterial effects through two screenings, with each involving a different set of arbitrarily chosen group of pathogens. The microorganisms producing antibacterial EPS were subsequently identified by morphological, biochemical and 16S rRNAbased phylogenetic analyses. Those EPS exhibiting broadest antibacterial activities were eventually characterised by Fouriertransform infrared spectroscopy (FTIR) and thin-layer chromatography (TLC). Results Eight EPS were found to display antibacterial effects against more than half of the pathogens and the microorganisms producing them were identified as Bacillus, Halomonas, Psychrobacter and Alcaligenes species. However, only two of these EPS were found to be the most active, with their MIC values ranging between 62.5 and 500 μg/ml. FTIR and TLC analyses revealed the presence of carboxyl, hydroxyl and amide as well as sulphate for the EPS, with glucose or fructose being the main sugar. Conclusion The results suggest that Mauritius seawater can be a source of biotechnologically useful microorganisms, producing EPS having potential as antimicrobial agents. DNA sequence data also suggest possible novel bacterial species.

No abstract

No abstract

As the largest habitat on Earth, the marine environment harbors various microorganisms of biotechnological potential. Indeed, microbial compounds, especially polysaccharides from marine species, have been attracting much attention for their applications within the medical, pharmaceutical, food, and other industries, with such interest largely stemming from the extensive structural and functional diversity displayed by these natural polymers. At the same time, the extreme conditions within the aquatic ecosystem (e.g., temperature, pH, salinity) may not only induce microorganisms to develop a unique metabolism but may also increase the likelihood of isolating novel polysaccharides with previously unreported characteristics. However, despite their potential, only a few microbial polysaccharides have actually reached the market, with even fewer being of marine origin. Through a synthesis of relevant literature, this review seeks to provide an overview of marine microbial polysaccharides, including their unique characteristics. In particular, their suitability for specific biotechnological applications and recent progress made will be highlighted before discussing the challenges that currently limit their study as well as their potential for wider applications. It is expected that this review will help to guide future research in the field of microbial polysaccharides, especially those of marine origin.