A process for extracellular thermostable lipase production by a novel Bacillus thermoamylovorans strain

Identification and phylogenetic characterization based on DNA sequences from RNA ribosomal genes of thermophilic microorganisms in a high elevation Andean tropical geothermal spring

Several microorganisms can survive in harsh acid environments in geothermal springs at high temperatures across the Equatorial Andes Mountains. However, little is known about their physiological features and phylogenetic composition. Here we identify thermophilic microorganisms (bacteria, fungi, and microalgae) hosted in an almost unexplored geothermal spring (known as “Aguas Hediondas”). The phylogeny of the cultures was determined by analyzing physiological features and DNA sequences of PCR products for 16S rRNA, ITS, and 23S rRNA genes. Twenty pure cultures were isolated from the samples, including 17 for bacteria, one for cyanobacterium, one for eukaryotic microalgae, and one for fungus. Most bacterial strains were gram-positive, spore-forming, and bacilli (Bacillus). Cyanobacterium strain belonged to Chroococcidiopsis and the eukaryotic microalgae to Chlorophyta. The unique fungal strain isolated was closely related to T. duponti. Through our study, isolated thermophilic bacteria, microalgae and fungi from the “Aguas Hediondas” geothermal spring were characterized and identified. This study represents one of the first extensive molecular characterizations of extremophile microbes in the Tropical Equatorial Andes. Keywords. microbial diversity; DNA markers; extremophiles; phylogenetics

Pineapple Peel Extract as an Effective Substrate for Esterase Production from Bacillus subtilis E9

Esterase, belonging to hydrolase class of enzymes catalyzes the cleavage and formation of ester bonds. Esterase producing isolates E9 and E46, isolated from pineapple waste enriched soil were identified as Bacillus subtilis E9 and Bacillus sp. E46 respectively. Bacillus subtilis E9 with 10 U/mg esterase activity in basal media was further chosen for media optimization studies. Several factors including the effect of organic solvents and fruit peel extracts were studied by one factor at a time optimization method and statistical models. An enhanced enzyme production of 250.50 U/mg could be obtained under the optimal conditions of pH 6.5, incubation time 25 h and 1.8%v/v of acetone extract of pineapple peel. The four-stage purification improved the purity of the enzyme by 1.5-fold with 5.3% recovery and specific activity of 384 U/mg. The monomeric nature and the molecular weight (45 KDa) of the enzyme were determined by performing SDS PAGE and its activity was confirmed by zymogram analysis. The substrate specificity of the purified fraction exhibited a higher activity towards lower chain length esters, indicating the enzyme as esterase. The partially purified esterase showed an optimal temperature of 40 °C at an optimum pH of 7. K_m and V_max of the enzyme were 1.12 mM and 1.18 mM of released pNP · min^-1 respectively.

Production optimization, characterization, and covalent immobilization of a thermophilic Serratia rubidaea lipase isolated from an Algerian oil waste

A new thermophilic non-induced lipase producer named Serratia rubidaea strain Nehal-mou was isolated from oil waste in Tissemsilat, Algeria. The most influential lipase production parameters were screened by the Plackett-Burman design for enhancing enzyme yield. An optimum condition of a 1.5% of glucose, a 0.01% of potassium, and a 0.025% of manganese contents resulted in a 41.13 U/mL. This yield was 6.29 times higher than the one achieved before the application of the Box-Behnken Design. Lipase activity showed a high organic solvent tolerance following its exposure to hexane, ethanol, methanol, and acetone. Lipase was also perfectly stable in the presence of 10 mM Fe²⁺, K⁺, and Na⁺ ions with more than 75% of the retaining activity. The enzyme half-life times were 22 h, 90 min, and 25 min at 50, 60, and 70 °C respectively. Polyvinyl alcohol (PVA)/boric acid/Starch/CaCO₃ were utilized as a carrier for lipase covalent immobilization in order to be used efficiently. The Scanning Electron Microscopy (SEM) Technique and the Fourier Transform Infrared Spectroscopy (FTIR) Method confirmed the covalent bonding success and the excellent carrier characteristics. Thus, the immobilization yield reached 73.5% and the optimum temperature was shifted from 40 to 65 °C. The immobilized lipase kept 80% of its total activity after 10 cycles and had 3 and 3.2-fold half-lives at 70, and 80 °C respectively compared to the free enzyme.

A combined treatment using ethylmethane sulfonate and ultraviolet light to compare amylase production by three Bacillus sp. isolates

In this study, three Bacillus sp.-producing amylase enzymes were isolated from soil samples and identified using 16S rDNA sequence analysis. Amylase production and total protein productions were spectrophotometrically measured. The following media were tested to increase enzyme production: LB medium and molasses. Three Bacillus sp. were identified as follows: Bacillus subtilis subtilis, Bacillus thuringiensis, and Bacillus cereus. Amylase production levels were in the range of 10 U/mL, whereas total protein production levels were at 15 mg/mL. Higher amylase activity was found in the Bacillus subtilis isolate. Ethylmethane sulfonate (EMS) and ultraviolet (UV) mutagenesis in combination were applied to compare amylase production. Amylase activity was increased to around 58% in the treatment with 0.03 mL of EMS and UV when compared to the control group. A pilot scale bioreactor with a total working volume of 10 liters was used to produce amylase by B. subtilis subtilis. In conclusion, B. subtilis subtilis can be used to produce amylase enzyme for various industrial purposes, and, for the first time, the amylase activities of B. subtilis can be enhanced with EMS and UV treatment.

Demonstrating the viability of halolipase production at a mechanically stirred tank biological reactor

The definition of halophiles as "the coming stars of industrial biotechnology" in a recent review demands new research efforts for their efficient production at bioreactor scale. In this sense, the scarcity of information about halolipases production has furthered the research on the viability of Halomonas sp. LM1C culture in a mechanically stirred bioreactor. The operating conditions have been optimized by means of a Central Composite Face-Centered (CCFC) design. The operation at low aerations (0.25 vvm) and moderate agitation rates (583 rpm) led to activity levels near 8000 U/L, which clearly surpasses the typical values detected for other extremophilic enzymes. The process at optimum conditions has been kinetically characterized and the oxygen volumetric mass transfer coefficient (K_La) has been determined.

Identification and sequence analyses of novel lipase encoding novel thermophillic bacilli isolated from Armenian geothermal springs

BACKGROUND

Among the huge diversity of thermophilic bacteria mainly bacilli have been reported as active thermostable lipase producers. Geothermal springs serve as the main source for isolation of thermostable lipase producing bacilli. Thermostable lipolytic enzymes, functioning in the harsh conditions, have promising applications in processing of organic chemicals, detergent formulation, synthesis of biosurfactants, pharmaceutical processing etc.

RESULTS

In order to study the distribution of lipase-producing thermophilic bacilli and their specific lipase protein primary structures, three lipase producers from different genera were isolated from mesothermal (27.5-70 °C) springs distributed on the territory of Armenia and Nagorno Karabakh. Based on phenotypic characteristics and 16S rRNA gene sequencing the isolates were identified as Geobacillus sp., Bacillus licheniformis and Anoxibacillus flavithermus strains. The lipase genes of isolates were sequenced by using initially designed primer sets. Multiple alignments generated from primary structures of the lipase proteins and annotated lipase protein sequences, conserved regions analysis and amino acid composition have illustrated the similarity (98-99%) of the lipases with true lipases (family I) and GDSL esterase family (family II). A conserved sequence block that determines the thermostability has been identified in the multiple alignments of the lipase proteins.

CONCLUSIONS

The results are spreading light on the lipase producing bacilli distribution in geothermal springs in Armenia and Nagorno Karabakh. Newly isolated bacilli strains could be prospective source for thermostable lipases and their genes.

Kinetic characterization and fed-batch fermentation for maximal simultaneous production of esterase and protease from Lysinibacillus fusiformis AU01

The simultaneous production of intracellular esterase and extracellular protease from the strain Lysinibacillus fusiformis AU01 was studied in detail. The production was performed both under batch and fed-batch modes. The maximum yield of intracellular esterase and protease was obtained under full oxygen saturation at the beginning of the fermentation. The data were fitted to the Luedeking-Piret model and it was shown that the enzyme (both esterase and protease) production was growth associated. A decrease in intracellular esterase and increase in the extracellular esterase were observed during late stationary phase. The appearance of intracellular proteins in extracellular media and decrease in viable cell count and biomass during late stationary phase confirmed that the presence of extracellular esterase is due to cell lysis. Even though the fed-batch fermentation with different feeding strategies showed improved productivity, feeding yeast extract under DO-stat fermentation conditions showed highest intracellular esterase and protease production. Under DO-stat fed-batch cultivation, maximum intracellular esterase activity of 820 × 10³ U/L and extracellular protease activity of 172 × 10³ U/L were obtained at the 16th hr. Intracellular esterase and extracellular protease production were increased fivefold and fourfold, respectively, when compared to batch fermentation performed under shake flask conditions.

Scaling-up and ionic liquid-based extraction of pectinases from Aspergillus flavipes cultures

The viability of the scaling-up of pectinases production by Aspergillus flavipes at 5L-bioreactor scale has been demonstrated by keeping constant the power input, and a drastic increase in the endo- and exopectinolytic enzyme production was recorded (7- and 40-fold, respectively). The main process variables were modelled by means of logistic and Gompertz equations. In order to overcome the limitations of the conventional downstream strategies, a novel extraction strategy was proposed on the basis of the adequate salting-out potential of two biocompatible cholinium-based ionic liquids (N_1112OHCl and N_1112OHH₂PO₄) in aqueous solutions of Tergitol, reaching more than 90% of extraction.

Isolation and characterization of a thermostable lipase from Bacillus thermoamylovorans NB501

Two thermophilic bacterial strains, Bacillus thermoamylovorans NB501 and NB502, were isolated from a high-temperature aerobic fermentation reactor system that processes tofu refuse (okara) in the presence of used soybean oil. We cloned a lipase gene from strain NB501, which secretes a thermophilic lipase. The biochemical characteristics of the recombinant enzyme (Lip501r) were elucidated. Lip501r is monomeric in solution with an apparent molecular mass of 38 kDa on SDS-PAGE. The optimal pH and apparent optimal temperature of Lip501r were 8 and 60°C, respectively. Supplementation of 5 mM Ca²⁺ enhanced the thermostability, and the enzyme retained 56% of its activity for 30 min at 50°C. Lip501r was active on a wide range of substrates with different lengths of p-nitrophenyl (pNP) esters, and showed a remarkably higher activity with pNP-myristate. The K_m and V_max values for pNP-butyrate in the presence of 5 mM CaCl₂ were 1.8 mM and 220 units/mg, respectively. The possible industrial use of the thermophilic lipase in modifying edible oil was explored by examining the degradation of soybean oil. A TLC analysis of the degraded products indicated that Lip501r is an 1,3-position specific lipase. A homology modeling study revealed that helix α6 in the lid domain of NB501 lipase was shorter than that of lipases from the Geobacillus group.

A RAPD based study revealing a previously unreported wide range of mesophilic and thermophilic spore formers associated with milk powders in China

Aerobic spore forming bacteria are potential milk powder contaminants and are viewed as indicators of poor quality. A total of 738 bacteria, including both mesophilic and thermophilic, isolated from twenty-five powdered milk samples representative of three types of milk powders in China were analyzed based on the random amplified polymorphic DNA (RAPD) protocol to provide insight into species diversity. Bacillus licheniformis was found to be the most prevalent bacterium with greatest diversity (~43% of the total isolates) followed by Geobacillus stearothermophilus (~21% of the total isolates). Anoxybacillus flavithermus represented only 8.5% of the total profiles. Interestingly, actinomycetes represented a major group of the isolates with the predominance of Laceyella sacchari followed by Thermoactinomyces vulgaris, altogether comprising of 7.3% of the total isolates. Out of the nineteen separate bacterial species (except five unidentified groups) recovered and identified from milk powders, twelve proved to belong to novel or previously unreported species in milk powders. Assessment and characterization of the harmful effects caused by this particular micro-flora on the quality and safety of milk powders will be worth doing in the future.

Ionic liquids for the concomitant use in extremophiles lysis and extremozymes extraction

Ionic liquids have been successfully proposed to modify membrane permeability in cultures of a model extremophilic bacterium Thermus thermophilus HB27, which makes up the first time that aqueous solutions of these molten salts are applied in downstream stages of this kind of microorganisms. The presence of 1g/L of C10MIMCl entails a great solubilisation of cell biomass, thus allowing the release of intracellular and membrane-bound enzyme. The influence on the enzyme activity of two inorganic salts such as Na2CO3 and (NH4)2SO4, selected on the basis of their high salting out potential and biocompatibility with enzymes, respectively, was investigated. In parallel, their ability to trigger phase segregation was confirmed in the presence of the enzyme crude, leading to very high levels of enzyme extraction (96%). The validity of the strategy was confirmed by operating at bioreactor scale, and the main bioprocess parameters were obtained by modelling the experimental data.

Draft Genome Sequences of Four Bacillus thermoamylovorans Strains Isolated from Milk and Acacia Gum, a Food Ingredient

The thermophilic bacterium Bacillus thermoamylovorans produces highly heat-resistant spores that can contaminate food products, leading to their spoilage. Here, we present the whole-genome sequences of four B. thermoamylovorans strains, isolated from milk and acacia gum.

Production and characterization of a halo-, solvent-, thermo-tolerant alkaline lipase by Staphylococcus arlettae JPBW-1, isolated from rock salt mine

Studies on lipase production and characterization were carried out with a bacterial strain Staphylococcus arlettae JPBW-1 isolated from rock salt mine, Darang, HP, India. Higher lipase activity has been obtained using 10 % inoculum with 5 % of soybean oil as carbon source utilizing a pH 8.0 in 3 h at 35 °C and 100 rpm through submerged fermentation. Partially purified S. arlettae lipase has been found to be active over a broad range of temperature (30-90 °C), pH (7.0-12.0) and NaCl concentration (0-20 %). It has shown extreme stability with solvents such as benzene, xylene, n-hexane, methanol, ethanol and toluene up to 30 % (v/v). The lipase activity has been found to be inhibited by metal ions of K(+), Co(2+) and Fe (2+) and stimulated by Mn(2+), Ca(2+) and Hg(2+). Lipase activity has been diminished with denaturants, but enhanced effect has been observed with surfactants, such as Tween 80, Tween 40 and chelator EDTA. The K m and V max values were found to be 7.05 mM and 2.67 mmol/min, respectively. Thus, the lipase from S. arlettae may have considerable potential for industrial application from the perspectives of its tolerance towards industrial extreme conditions of pH, temperature, salt and solvent.

North Western Spain hot springs are a source of lipolytic enzyme-producing thermophilic microorganisms

Several hot springs in Galicia (North Western Spain) have been investigated as potential sources of lipolytic enzyme-producing thermophilic microorganisms. After isolating 12 esterase producing strains, 9 of them were assured to be true lipase producers, and consequently grown in submerged cultures, obtaining high extracellular activities by two of them. Furthermore, a preliminary partial characterization of the crude lipase, obtained by ultrafiltration of the cell-free culture supernatant, was carried out at several pH and temperature values. It is outstanding that several enzymes turned out to be multiextremozymes, since they had their optimum temperature and pH at typical values from thermoalkalophiles. The thermal stability in aqueous solution of the crude enzymes was also assayed, and the influence of some potential enzyme stabilizing compounds was tested. Finally, the viability of the selected microorganisms has been demonstrated at bioreactor scale.