Screening and Characterization of Halophilic Bacteria With Industrial Enzymes from Salt Lake Razazah, Karbala, Iraq

Abstract

A total of 218 halophilic bacterial isolates were obtained from Lake Razazah, west of Karbala, Iraq. Optimum pH and temperature were 7.5 and 37 °C, respectively. According to optimal growth at different salt concentration, the slightly halophilic bacteria were the most abundant isolates with the frequency of 68%. The isolated bacteria were screened for the production of extracellular amylase, alkaline amylase, protease, alkaline protease, lipase, alkaline lipase, pectinase and cellulase. The production of pectinase (55.8%), amylase (52.6%) and lipase (50.0%) were observed in almost half of the halophilic bacteria. Alkaline amylase and alkaline lipase production were reported in less than one third (30%) of isolates. Phylogenetic analysis16S rRNA sequences indicated that all isolates were members of eight genera of the domain Bacteria, including Bacillus, Halobacillus, Virgibacillus, Oceanobacillus, Staphylococcus, Pseudomonas, Idiomarina and Halomonas. The predominant commercial enzymes producers in current study were Halobacillus sp. K51 and Halomonas sp. K46 with the ability to produce 7 out of 8 exoenzymes. The presented data shows that despite drought, dehydration, increased concentrations of salt and contaminants, Lake Razazah represents an untapped source of halophilic bacteria biodiversity.

Bioprospecting for Novel Halophilic and Halotolerant Sources of Hydrolytic Enzymes in Brackish, Saline and Hypersaline Lakes of Romania

“…The taxonomic identification of 72 bacterial isolates revealed that most of them were related to species of the genera Halomonas (23 isolates) and Bacillus (21 isolates). All of the five investigated lakes harbored representatives of these two taxonomic groups, this observation being in accordance with other previous studies performed in various saline and hypersaline environments around the world [39,48,49,60]. The Bacillus isolates were generally halotolerant and exhibited higher hydrolytic activities compared to the other cultured taxa.…”

“…These results are partially in line with those reported in the present paper. However, very different results were reported in another two studies carried out in hypersaline habitats in Morocco [52] and Iraq [49]. While the former [52] reported the prevalence of bacteria producing cellulase and pectinase, the latter [49] showed that the enzymes most frequently produced by bacterial isolates were pectinase, amylase and lipase.…”

“…However, very different results were reported in another two studies carried out in hypersaline habitats in Morocco [52] and Iraq [49]. While the former [52] reported the prevalence of bacteria producing cellulase and pectinase, the latter [49] showed that the enzymes most frequently produced by bacterial isolates were pectinase, amylase and lipase. On the other hand, halophilic archaea recovered from various Algerian hypersaline habitats have shown higher hydrolytic abilities compared to the isolates reported in the present paper, most of them being able to produce esterase, inulinase and gelatinase [40] or esterase, protease and amylase [50].…”

“…Over recent decades, saline and hypersaline environments have gained considerable attention from the scientific community due to their natural inhabitants, which have adapted to synthesize various biotechnologically valuable compounds such as hydrolytic enzymes [8][9][10]. Several studies performed in various areas around the world have reported the discovery of different halophilic and halotolerant microbial taxa capable of producing robust hydrolases that retain their catalytic activity over a wide range of salinities and, in some cases, even under extreme conditions of pH and temperature [16,39,40,[48][49][50][51][52]. Although various such extremozymes have been described to date, there are still many unexplored saline and hypersaline environments that could harbor novel microbial strains able to produce biomolecules with favorable characteristics for biotechnological applications.…”

Phylogenetic diversity and biotechnological potentials of marine bacteria from continental slope of eastern Arabian Sea

“…and Staphylococcus sp. are able to produce amylases, gelatinase, cellulase, and lipase [23]. Similarly, Halomonas and Staphylococcus genera were found to be potent extracellular hydrolytic enzyme producers.…”