Enhanced Biodegradation of Alkane Hydrocarbons and Crude Oil by Mixed Strains and Bacterial Community Analysis

In this study, two strains, Acinetobacter sp. XM-02 and Pseudomonas sp. XM-01, were isolated from soil samples polluted by crude oil at Bohai offshore. The former one could degrade alkane hydrocarbons (crude oil and diesel, 1:4 (v/v)) and crude oil efficiently; the latter one failed to grow on alkane hydrocarbons but could produce rhamnolipid (a biosurfactant) with glycerol as sole carbon source. Compared with pure culture, mixed culture of the two strains showed higher capability in degrading alkane hydrocarbons and crude oil of which degradation rate were increased from 89.35 and 74.32?±?4.09 to 97.41 and 87.29?±?2.41 %, respectively. In the mixed culture, Acinetobacter sp. XM-02 grew fast with sufficient carbon source and produced intermediates which were subsequently utilized for the growth of Pseudomonas sp. XM-01 and then, rhamnolipid was produced by Pseudomonas sp. XM-01. Till the end of the process, Acinetobacter sp. XM-02 was inhibited by the rapid growth of Pseudomonas sp. XM-01. In addition, alkane hydrocarbon degradation rate of the mixed culture increased by 8.06 to 97.41 % compared with 87.29 % of the pure culture. The surface tension of medium dropping from 73.2?×?10^?3 to 28.6?×?10^?3 N/m. Based on newly found cooperation between the degrader and the coworking strain, rational investigations and optimal strategies to alkane hydrocarbons biodegradation were utilized for enhancing crude oil biodegradation.     

Isolation of Biphenyl and Polychlorinated Biphenyl-Degrading Bacteria and Their Degradation Pathway

Four strains of biphenyl-degrading bacteria were isolated from a sewage and identified from the Rhodococcus genus (SK-1, SK-3, and SK-4) and Aquamicrobium genus (SK-2) by 16S rRNA sequence. Among these strains, strain SK-2 was most suitable for biphenyl degradation. When 0.65, 1.3, 2.6, or 3.9 mM of biphenyl was used, the biphenyl was completely degraded within 24 and 96 h of culture, respectively. However, in the case of 6.5 and 9.75 mM of biphenyl, the biphenyl degradation yields were about 80 % and 46.7 % after 120 h of culture, respectively. The isolated strains could degrade a broad spectrum of aromatic compounds including high-chlorinated polychlorinated biphenyl (PCB) congeners in the presence of biphenyl. In addition, strain SK-2 could utilize PCB congeners containing one to six chlorine substituents such as 2,2′,4,4′,5,5′-hexachlorobiphenyl. The PCB utilization rate by the strain SK-2 was increased compared to that of other PCB congener-utilizing bacteria. The four isolates metabolized 4-chlorobiphenyl to 4-chlorobenzoic acid and 2-hydroxy-6-oxo-6-(4′-chlorophenyl)-hexa-2,4-dienoic acid. These results suggest the isolated strains might be good candidates for the bioremediation of PCB-contaminated soil, especially high-saline soils.     

A New Alkaliphilic Cold-Active Esterase from the Psychrophilic Marine Bacterium Rhodococcus sp.: Functional and Structural Studies and Biotechnological Potential

The special features of cold-adapted lipolytic biocatalysts have made their use possible in several industrial applications. In fact, cold-active enzymes are known to be able to catalyze reactions at low temperatures, avoiding side reactions taking place at higher temperatures and preserving the integrity of products. A lipolytic gene was isolated from the Arctic marine bacterium Rhodococcus sp. AW25M09 and expressed in Escherichia coli as inclusion bodies. The recombinant enzyme (hereafter called RhLip) showed interesting cold-active esterase activity. The refolded purified enzyme displayed optimal activity at 30 °C and was cold-active with retention of 50 % activity at 10 °C. It is worth noting that the optimal pH was 11, and the low relative activity below pH 10 revealed that RhLip was an alkaliphilic esterase. The enzyme was active toward short-chain p-nitrophenyl esters (C2–C6), displaying optimal activity with the butyrate (C4) ester. In addition, the enzyme revealed a good organic solvent and salt tolerance. These features make this an interesting enzyme for exploitation in some industrial applications.     

Characterization of Truncated <Emphasis Type="Italic">dsz</Emphasis> Operon Responsible for Dibenzothiophene Biodesulfurization in <Emphasis Type="Italic">Rhodococcus</Emphasis> sp. FUM94

Numerous desulfurizing bacteria from the Rhodococcus genus harbor conserved dsz genes responsible for the degradation of sulfur compounds through 4S pathway. This study describes a newly identified desulfurizing bacterium, Rhodococcus sp. FUM94, which unlike previously identified strains encodes a truncated dsz operon. DNA sequencing revealed a frameshift mutation in the dszA gene, which led to an alteration of 66 amino acids and deletion of other C-terminal 66 amino acids. The resulting DszA polypeptide was shorter than DszA in Rhodococcus sp. IGTS8 reference strain. Despite the truncation, desulfurizing activity of the operon was observed and attributed to the removal of an overlap of dszA and dszB genes, and lack of active site in the altered region. Desulfurization experiments resulted in specific production rate of 6.3 mmol 2-hydroxy biphenyl (kgDCW)^?1 h^?1 at 2 g l^?1 biocatalyst concentration and 68.8% biodesulfurization yield at 20 g l^?1 biocatalyst concentration, both at 271 μM dibenzothiophene concentration which is comparable to similar wild-type biocatalysts.     

Screening and Production Study of Microbial Xylanase Producers from Brazilian Cerrado

Hemicelluloses are polysaccharides of low molecular weight containing 100 to 200 glycosidic residues. In plants, the xylans or the hemicelluloses are situated between the lignin and the collection of cellulose fibers underneath. The xylan is the most common hemicellulosic polysaccharide in cell walls of land plants, comprising a backbone of xylose residues linked by β-1,4-glycosidic bonds. So, xylanolytic enzymes from microorganism have attracted a great deal of attention in the last decade, particularly because of their biotechnological characteristics in various industrial processes, related to food, feed, ethanol, pulp, and paper industries. A microbial screening of xylanase producer was carried out in Brazilian Cerrado area in Selviria city, Mato Grosso do Sul State, Brazil. About 50 bacterial strains and 15 fungal strains were isolated from soil sample at 35 °C. Between these isolated microorganisms, a bacterium Lysinibacillus sp. and a fungus Neosartorya spinosa as good xylanase producers were identified. Based on identification processes, Lysinibacillus sp. is a new species and the xylanase production by this bacterial genus was not reported yet. Similarly, it has not reported about xylanase production from N. spinosa. The bacterial strain P5B1 identified as Lysinibacillus sp. was cultivated on submerged fermentation using as substrate xylan, wheat bran, corn straw, corncob, and sugar cane bagasse. Corn straw and wheat bran show a good xylanase activity after 72 h of fermentation. A fungus identified as N. spinosa (strain P2D16) was cultivated on solid-state fermentation using as substrate source wheat bran, wheat bran plus sawdust, corn straw, corncob, cassava bran, and sugar cane bagasse. Wheat bran and corncobs show the better xylanase production after 72 h of fermentation. Both crude xylanases were characterized and a bacterial xylanase shows optimum pH for enzyme activity at 6.0, whereas a fungal xylanase has optimum pH at 5.0–5.5. They were stable in the pH range 5.0–10.0 and 5.5–8.5 for bacterial and fungal xylanase, respectively. The optimum temperatures were 55C and 60 °C for bacterial and fungal xylanase, respectively, and they were thermally stable up to 50 °C.     

Microbial Degradation of Chlorogenic Acid by a <Emphasis Type="Italic">Sphingomonas</Emphasis> sp. Strain

In order to elucidate the metabolism of chlorogenic acid by environmental microbes, a strain of Sphingomonas sp. isolated from tobacco leaves was cultured under various conditions, and chlorogenic acid degradation and its metabolites were investigated. The strain converting chlorogenic acid was newly isolated and identified as a Sphingomonas sp. strain by 16S rRNA sequencing. The optimal conditions for growth and chlorogenic acid degradation were 37 °C and pH 7.0 with supplementation of 1.5 g/l (NH₄)₂SO₄ as the nitrogen source and 2 g/l chlorogenic acid as the sole carbon source. The maximum chlorogenic acid tolerating capability for the strain was 5 g/l. The main metabolites were identified as caffeic acid, shikimic acid, and 3,4-dihydroxybenzoic acid based on gas chromatography-mass spectrometry analysis. The analysis reveals the biotransformation mechanism of chlorogenic acid in microbial cells isolated from the environment.     

Isolation and Characterization of Acrylamidase from <Emphasis Type="Italic">Arthrobacter</Emphasis> sp. DBV1 and Its Ability to Biodegrade Acrylamide

Although acrylamide finds diverse industrial applications, its presence in the environment is hazardous due to its carcinogenic, neurotoxic, and teratogenic properties. In spite of the general toxicity of acrylamide in the monomer form, some microorganisms are able to use it as a source of energy by catabolizing it to ammonia and acrylic acid by means of acrylamidase (EC 3.5.1.4). The present work reports on a novel soil isolate as an acrylamide-degrading bacteria. Based on biochemical characterization and 16S ribosomal RNA (rRNA) gene sequence, the bacterial strain was identified as Gram-positive Arthrobacter sp. DBV1. The optimum growth conditions were found to be temperature (30 °C) and pH 6.0 to 7.0. Evaluation of the effect of concentration of acrylamide (10–50 mM) incorporated into minimal medium showed maximum growth of Arthrobacter sp. DBV1 at 30 mM acrylamide. The biodegradation of acrylamide was confirmed by HPLC analysis. Acrylamidase was isolated and characterized for temperature and pH optima, substrate specificity by using different amides, and the effect of different activators/inhibitors such as metal ions and amino acids. These finding suggests that the strain could be attractive for biodegradation of acrylamide from the environment and also possibly from foods containing preformed acrylamide.     

Screening, Gene Sequencing and Characterising of Lipase for Methanolysis of Crude Palm Oil

Staphylococcus sp. WL1 lipase (LipFWS) was investigated for methanolysis of crude palm oil (CPO) at moderate temperatures. Experiments were conducted in the following order: searching for the suitable bacterium for producing lipase from activated sludge, sequencing lipase gene, identifying lipase activity, then synthesising CPO biodiesel using the enzyme. From bacterial screening, one isolated specimen which consistently showed the highest extracellular lipase activity was identified as Staphylococcus sp. WL1 possessing lipFWS (lipase gene of 2,244 bp). The LipFWS deduced was a protein of 747 amino acid residues containing an α/β hydrolase core domain with predicted triad catalytic residues to be Ser474, His704 and Asp665. Optimal conditions for the LipFWS activity were found to be at 55 °C and pH 7.0 (in phosphate buffer but not in Tris buffer). The lipase had a K _M of 0.75 mM and a V _max of 0.33 mM?min^?1 on p-nitrophenyl palmitate substrate. The lyophilised crude LipFWS performed as good as the commonly used catalyst potassium hydroxide for methanolysis of CPO. ESI-IT-MS spectra indicated that the CPO was converted into biodiesel, suggesting that free LipFWS is a worthy alternative for CPO biodiesel synthesis.     

Stability of Polymer and Surfactant Mixture Enhanced Foams in the Presence of Oil Under Static and Dynamic Conditions

Three different types of foaming agents including hydrocarbon surfactant TQ01, partial fluorinated surfactant BF01, and per-fluorinated surfactant QF01 exhibited good foaming ability and foam stability under 95°C high temperature and 32,325 ppm salinity conditions. The oil-tolerance ability order with respect to Malaysia Off-shore (MOS) crude oil for surfactant TQ01, BF01, and QF01 is TQ01 < BF01 < QF01. Introduction of polymer into the foam formula could significantly increase foam stability. Different polymers show different abilities of increasing foam stability. Spreading coefficient and entering coefficient are close to zero for surfactant BF01 foaming system and much less than zero for surfactant QF01 foaming system, so the oil-resistance ability of foam generated by surfactant QF01 is the strongest. For surfactant TQ01 foaming system, the calculated spreading coefficient and entering coefficient are greater than zero; therefore, the TQ01 foam system is more sensitive to MOS crude oil and its oil-resistance ability is the poorest. Core flooding test indicated that using the 0.4% BF01 and 0.2% YH1096 combined foaming formula could increase the pressure drop across the porous media significantly, indicating that strong foam was generated in the presence of MOS crude oil.     

Pseudomonas stutzeri Strain Possessing a Self-Transmissible TOL-Like Plasmid Degrades Phenol and Promotes Maize Growth in Contaminated Environments

Phenol is volatile organic pollutant that plants can little degrade. For complete degradation of volatile pollutants, we introduced Pseudomonas stutzeri strain P7 to phenol-contaminated soils. The strain effectively degraded phenol and even promoted plant growth. A TOL-like plasmid was detected in the strain and found to be responsible for phenol degradation and self-transmissible. In addition, phenol degradation by strain P7 was more rapid in the contaminated soils with than without plants over the full course of the experiment; especially by 5 days, the phenol concentration was reduced by about 30 % in soil without plants and reduced by about 50–65 % in soil with plants. This situation also occurred when inoculated with different transconjugants. Furthermore, transfer frequencies of TOL-like plasmid were significantly higher in soil with than without plants. Populations of rifampin-resistant P7 strain remained relatively constant for 20 days, while the number of rhizosphere bacteria that contained the degradative plasmids gradually increased at the later stages, suggesting that plants might stimulate plasmid transfer from strain P7 to indigenous bacteria, one possible reason for plant enhancing microbial degradation. This is attractive for implementation of combinations of phytoremediation and bioaugmentation in degradation of volatile pollutants that plants can little degrade.     

Identification and Characterization of a High Efficiency Aniline Resistance and Degrading Bacterium MC-01

Biodegradation is one of the important methods for the treatment of industrial wastewater containing aniline. In this paper, a degrading bacterium named MC-01, which could survive in high concentration aniline wastewater, was screened from industrial wastewater containing aniline and sludge. MC-01 was preliminarily identified as Ochrobactrum sp. based on the amplified 16S rDNA gene sequence and Biolog system identification. MC-01 was highly resistant to aniline. After 24-h culture under aniline concentration of 6500 mg/L, the amount of bacterium survived still remained 0.05 × 10⁶ CFU/mL. Experiments showed that there was no coupling expression between the growth of MC-01 and aniline degradation. The optimum growth conditions in LB culture were pH 6.0, 30 °C of temperature, and 4% of incubation amount, respectively. And the optimum conditions of aniline degradation of MC-01 were pH 7.0, 45 °C of temperature, and 3.0% of salt concentration, respectively. The degradation rate of MC-01 (48 h) in different aniline concentrations (200~1600 mg/L) was stable under the optimum conditions, which could reach more than 75%.     

Production and Properties of a Surface-Active Lipopeptide Produced by a New Marine Brevibacterium luteolum Strain

Microbial-derived surfactants are molecules of great interest due to their environmentally friendly nature and low toxicity; however, their production cost is not competitive when compared to synthetics. Marine microorganisms are exposed to extremes of pressure, temperature, and salinity; hence, they can produce stable compounds under such conditions that are useful for industrial applications. A screening program to select marine bacteria able to produce biosurfactant using low-cost substrates (mineral oil, sucrose, soybean oil, and glycerol) was conducted. The selected bacterial strain showed potential to synthesize biosurfactants using mineral oil as carbon source and was identified as Brevibacterium luteolum. The surface-active compound reduced the surface tension of water to 27 mN m^?1 and the interfacial tension (water/hexadecane) to 0.84 mN m^?1 and showed a critical micelle concentration of 40 mg L^?1. The biosurfactant was stable over a range of temperature, pH, and salt concentration and the emulsification index (E₂₄) with different hydrocarbons ranging from 60 to 79 %. Structural characterization revealed that the biosurfactant has a lipopeptide nature. Sand washing removed 83 % of crude oil demonstrating the potential of the biosurfactants (BS) for bioremediation purposes. The new marine B. luteolum strain showed potential to produce high surface-active and stable molecule using a low-cost substrate.     

A Cold-Adapted and Organic Solvent-Tolerant Lipase from a Psychrotrophic Bacterium Pseudomonas sp. Strain YY31: Identification, Cloning, and Characterization

A novel cold-adapted lipase (designated as LipYY31) was obtained from a psychrotrophic Pseudomonas sp. YY31. The strain YY31 was gram-negative, rod shaped, motile by means of one polar flagellum, and exhibited chemotaxis toward oil droplets under a microscope. The strain displayed remarkable degradation of edible oil and fat even at 5 °C. The LipYY31 DNA fragment contains an open reading frame of 1,410 bp which encoded a protein of 470 amino acids with an estimated molecular mass of 49,584 Da. LipYY31 showed high sequence similarity to those of subfamily Ι.3 lipase and had a conserved GXSXG motif around the catalytic Ser residue. Its optimal temperature was 25–30 °C, and it retained 20–40 % of its activity at 0–5 °C. The optimal pH value was 8.0. The activity was strongly inhibited by Cd²⁺, Zn²⁺, EDTA and was highly dependent on Ca²⁺. Tricaprin and p-nitrophenyl caprate were the most favorable substrates among the triglycerides and p-nitrophenyl esters, respectively. LipYY31 also had high activity towards natural substrates including edible vegetable oils and animal fat. Furthermore, LipYY31 was very active and stable in the presence of several detergents and organic solvents. In particular, the lipase exhibited high stability against organic solvents such as methanol, ethanol, and isopropanol.     

Biosurfactant production under extreme environmental conditions by an efficient microbial consortium, ERCPPI-2

The biosurfactant production potential of a new microbial consortium of Enterobacter cloacae and Pseudomonas sp. (ERCPPI-2) which was isolated from heavy crude oil-contaminated soil in the south of Iran, has been investigated under extreme environmental conditions. The isolated consortium produces a biosurfactant mixture with excessive oil spreading and emulsification properties. This consortium was able to grow and produce biosurfactant at temperatures up to 70 °C, pressures up to 6000 psia, salinities up to 15% (w/v), and in the pH range 4-10. Besides, the optimum biosurfactant production conditions were found to be 40 °C and 7.0 for the temperature and pH value, respectively. These conditions gave the best biosurfactant production of 1.74 g/1 when the cells were grown on a minimal salt medium containing 1.0% (w/v) olive oil, 1.0% (w/v) sodium nitrate supplemented with 1.39% (w/v) K(2)HPO(4) at 40 °C and 150 rpm after 48 h of incubation. The ERCPPI-2 could reduce surface and interfacial tensions to 31.7 and 0.65 mN/m from the original values of 58.3 and 16.9 mN/m, respectively. The isolated consortium produced biosurfactant using heavy crude oil as the sole source of carbon and emulsified the available heavy crude oil up to E(24)=83.4%. The results of the core holder flooding tests at simulated reservoir conditions demonstrated that the oil recovery efficiency due to the injection of the cell-free biosurfactant solution was 27.2%, and the bacterium injection reduced the final residual oil saturations to below 3% at optimum conditions.     

Utilization of Banana Peel as a Novel Substrate for Biosurfactant Production by Halobacteriaceae archaeon AS65

In this study, biosurfactant-producing bacteria was evaluated for biosurfactant production by using banana peel as a sole carbon source. From the 71 strains screened, Halobacteriaceae archaeon AS65 produced the highest biosurfactant activity. The highest biosurfactant production (5.30 g/l) was obtained when the cells were grown on a minimal salt medium containing 35 % (w/v) banana peel and 1 g/l commercial monosodium glutamate at 30 °C and 200 rpm after 54 h of cultivation. The biosurfactant obtained by extraction with ethyl acetate showed high surface tension reduction (25.5 mN/m), a small critical micelle concentration value (10 mg/l), thermal and pH stability with respect to surface tension reduction and emulsification activity, and a high level of salt tolerance. The biosurfactant obtained was confirmed as a lipopeptide by using a biochemical test FT-IR, NMR, and mass spectrometry. The crude biosurfactant showed a broad spectrum of antimicrobial activity and had the ability to emulsify oil, enhance PAHs solubility, and oil bioremediation.     

The Wettability Alteration and the Effect of Initial Rock Wettability on Oil Recovery in Surfactant-based Enhanced Oil Recovery Processes

Wettablity alteration of rock surface is an important mechanism for surfactant-based enhanced oil recovery (EOR) processes. Two salt and temperature-tolerant surfactant formulations were developed based on the conditions of high temperature (97–120°C) and high salinity (20 × 10⁴ mg/L) reservoirs where a surfactant-based EOR process is attempted. Both the two sufactant formulations can achieve ultralow interfacial tension level (≤10^?3 mN/m) with crude oil after aging for 125 days at reservoir conditions. Wettability alteration of core slices induced by the two surfactant formulations was evalutated by measuring contact angles. Core flooding experiments were carried out to study the influence of initial rock wettabilities on oil recovery in the crude oil/surfactant/formation water/rock system. The results indicated that the two formulations could turn oil-wet core slices into water-wet at 90–120°C and 20 × 10⁴ mg/L salinity, while the water-wet core slices retained their hydrophilic nature. The core flooding experiments showed that the water-wet cores could yield higher oil recovery compared with the oil-wet cores in water flooding, surfactant, and subsequent water flooding process. The two surfactant formulations could successfully yield additional oil recovery in both oil-wet and water-wet cores.     

Random UV Mutagenesis Approach for Enhanced Biodegradation of Sulfonated Azo Dye, Green HE4B

The objective of the study was to execute mutant bacteria for efficient biodegradation of sulfonated azo dye, Green HE4B (GHE4B). UV irradiation was used to introduce random mutations in Pseudomonas sp. LBC1. Genetic alterations induced by UV irradiation in selected mutant bacteria were confirmed by random amplification of polymorphic DNA technique. The mutant bacteria named as Pseudomonas sp. 1 F reduced the time required for complete degradation of recalcitrant dye GHE4B by 25 % when compared with the wild one. The biodegradation was monitored by UV–Vis spectrophotometric analysis. Activities of enzymes like laccase, lignin peroxidase, veratryl alcohol oxidase, and NADH dichlorophenol indophenol reductase were found to be boosted in mutant bacteria as a consequence of UV-induced mutation. Matrix-assisted laser desorption/ionization-time of flight analysis of differentially expressed proteins of mutant bacteria suggested active role of antioxidant enzymes in the degradation of the dye. The degradation product was analyzed by Fourier transform infrared spectroscopy, high-performance thin-layer chromatography, and gas chromatography–mass spectrometry. Results revealed few variations in the degradation end products of wild-type and mutant bacteria. Phytotoxicity study underlined the safer biodegradation of GHE4B by mutant Pseudomonas sp. 1 F.     

Improvement of Strain Penicillium sp. EZ-ZH190 for Tannase Production by Induced Mutation

In the search for an efficient producer of tannase, Penicillium sp. EZ-ZH190 was subjected to mutagenesis using heat treatment and strain EZ-ZH290 was isolated. The maximum tannase in this mutant strain was 4.32 U/mL with an incubation period of 84 h as compared to wild strain EZ-ZH190 where the incubation period was 96 h with a maximum enzyme activity of 4.33 U/mL. Also, the Penicillium sp. EZ-ZH290 tannase had a maximum activity at 40 °C and pH 5.5. Then, the spores of strain EZ-ZH290 were subjected to γ irradiation mutagenesis and strain EZ-ZH390 was isolated. Strain EZ-ZH390 exhibited higher tannase activity (7.66 U/mL) than the parent strain EZ-ZH290. It was also found that Penicillium sp. EZ-ZH390 tannase had an optimum activity at 35 °C and a broad pH profile with an optimum at pH 5.5. The tannase pH stability of Penicillium sp. EZ-ZH390 and its maximum production of tannase followed the same trend for five generations confirming the occurrence of stable mutant. This paper is shown that γ irradiation can mutate the Penicillium sp. leading to increase the tannase production.     

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⁺, Co²⁺ and Fe ²⁺ and stimulated by Mn²⁺, Ca²⁺ and Hg²⁺. 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.     

Enhanced Inulin Saccharification by Self-Produced Inulinase from a Newly Isolated <Emphasis Type="Italic">Penicillium</Emphasis> sp. and its Application in <Emphasis Type="SmallCaps">d</Emphasis>-Lactic Acid Production

In order to find an alternative for commercial inulinase, a strain XL01 identified as Penicillium sp. was screened for inulinase production. The broth after cultivated was centrifuged, filtered, and used as crude enzyme for the following saccharification. At pH 5.0 and 50 °C, the crude enzyme released 84.9 g/L fructose and 20.7 g/L glucose from 120 g/L inulin in 72 h. In addition, simultaneous saccharification and fermentation of chicory flour for d-lactic acid production was carried out using the self-produced crude inulinase and Lactobacillus bulgaricus CGMCC 1.6970. A high d-lactic acid titer and productivity of 122.0 g/L and 1.69 g/(L h) was achieved from 120 g/L chicory flour in 72 h. The simplicity for inulinase production and the high efficiency for d-lactic acid fermentation provide a perspective and profitable industrial biotechnology for utilization of the inulin-rich biomass.