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Extremophiles are a major source for many industrially important biomolecules. Haloarchaea have been extensively studied for their ability to grow in extreme environments and the array of metabolites especially osmolytes they produce with resistance to extreme physical and chemical conditions. In the present study, we have studied the haloarchaeal isolates for their ability to produce industrially important biomolecules like—proteases, amylases, surfactants, antifreeze and antidesiccation proteins. The haloarchaea used in this study were isolated from fish sauce fermentation broth and belonged to Halorubrum sp. SS1 (KY053875.1), Halobacterium sp. SS2 (KY053876.1), Halococcus sp. AMS1 (KU995303.1), Halorhabdus sp. AMS6 (KU995310.1) and Halobacterium sp. SFF3 (KY053871.1). All the archaea isolated in this report had negligible amylase and surfactant activities but showed marginal protease activity. The isolates were also found to be producing significant antifreeze protein stable till 192 h and desiccation tolerant till 240 min of studies. This is the first report of microbial extracellular proteins exhibiting antidesiccation and antifreeze properties, thus introducing a new family of industrially important microbial proteins. These applications have immense potential in food preservation and processing.

Dandruff is one of the most common clinically manifested and studied scalp disorders. It has been associated with both bacteria and fungi. Bacteria and fungi inhabiting the scalp are known to influence each other and manifestation of dandruff. Fungal and bacterial isolates from scalp epithelial flakes (dandruff) were identified by rDNA sequencing. Local oils were tested for fungal and bacterial inhibition, interaction and biofilm formation, cell–cell interactions were studied by auto aggregation and surface thermodynamics studies. The isolates Bacillus sp.C2b1 (MK036745) and Malassezia sp. C2y1 (MK036746) were inhibited by Mahabhrungraj oil. The fungal morphological switch was evident and dependent on nutrition. Cell aggregation studies suggested the interaction of bacteria with yeast (non-pathogenic) phase of the fungus. Bacterial and yeast cells were found to be compatible for biofilm formation. The fungal mycelial surfaces were found to be conducive for interaction with both bacterial cells and yeast forms. The results here indicate the significance of mycelial phase of scalp-isolated fungus in interaction with the bacterial surfaces and also with self-yeast phase surface. This is the first report of the interaction between scalp-isolated microorganisms with respect to their surface interaction capabilities.

Background Azo dye effluents cause severe pollution problems in soil and water and affect their flora and fauna throughout the world. The combination of dye degrading bacteria in the gut of freshwater fish has been considered a prospective approach towards the development of a sustainable environment. In the southernmost part of India, especially in the Namakkal District of Tamil Nadu state, urbanization and industrial development lead to various environmental issues. In lieu, most of the earlier works were carried out on the bacterial dye degradation from soil and water sources, least concentration on the dye degradation from fish gut flora. The objective of this study was to analyze the role of dye degrading bacteria in the gut of freshwater fish collected from the study area. Results We have studied the aerobic degradation of remazol yellow reactive dye by bacteria forming the gut flora of exotic fish Oreochromis mossambica from river Cauvery at Pallipalayam of Namakkal District, India. Eight dye degrading gut isolates viz. Pseudomonas sp. AD1, Bacillus sp. AD2, Staphylococcus sp. AD3, Staphylococcus AD4, Enterobacter sp. AD5, Escherichia coli AD6, Streptococcus sp. AD7 and Clostridium sp. AD8 were obtained capable of growing in azo dye incorporated in Basic mineral medium (BMM) medium. Optimization study was carried out for various parameters for the selected isolates. Based on the growth, maximum growth was seen in Pseudomonas sp. AD1 (in 0–24 h) and minimum in Escherichia coli.AD 6 (in 72–96 h). Pseudomonas sp. AD1, Enterobacter sp.AD5, and Bacillus sp. AD 2 exhibited efficient dye degradation during 0–96 h analysis which was confirmed by FTIR analysis. Loss of azo group stretch at 1572–76 cm−1 and 1429 cm−1 and presence of primary (–NH2–) and secondary amides (–NH2–), aliphatic –C–N– stretching and confirmed –C–S– stretching in FTIR analysis confirms the breaking down of the azo bond. Conclusion This study showed that there is a platform for using the bacterial flora of fish gut that paves a prominent way in the degradation of Azo dye.

Isolates were obtained from intertidal zone site samples from all five western and one eastern coastal states of India and were screened. These ecophysiological groups of aerobic, mesophilic, heterotrophic, sporulating, and bioemulsifier-producing bacteria were from Planococcaceae and Bacillaceae. This is the first report of bioemulsifier production by Sporosarcina spp., Lysinibacillus spp., B. thuringiensis, and B. flexus. In this group, Solibacillus silvestris AM1 was found to produce the highest emulsification activity (62.5 %EI) and the sample that yielded it was used to isolate the ecophysiological group of non-bioemulsifier-producing, hydrocarbon-degrading bacteria (belonging to Chromatiales and Bacillales). These yielded hitherto unreported degrader, Rheinheimera sp. CO6 which was selected for the interaction studies (in a microcosm) with bioemulsifier-producing S. silvestris AM1. The gas chromatographic study of these microcosm experiments revealed increased degradation of benzene, toluene, and xylene (BTX) and the growth of Rheinheimera sp. CO6 in the presence of bioemulsifier produced by S. silvestris AM1. Enhancement of the growth of S. silvestris AM1 in the presence of Rheinheimera sp. CO6 was observed possibly due to reduced toxicity of BTX suggesting mutualistic association between the two. This study elucidates the presence and interaction between enhancers and degraders in a hydrocarbon-contaminated intertidal zone and contributes to the knowledge during application of the two in remediation processes.