Production of lipase from Penicillium sp. using waste oils and Nopalea cochenillifera

The present communication deals with the production of lipase from Penicillium sp. using waste oils and palm cactus (Nopalea cochenillifera) especially as nutrient source of low cost. Two different waste oils were tested: waste frying oil from an industrial kitchen and waste lubricating oil (WLO) from a gas station. Using Doehlert experimental design and response surface methodology, the optimum conditions for lipase production were 96?h fermentation, WLO as the inductor, with specific activity of 0.22?UA?mg^?1. The enzyme was able to remain with more than 58% of its original activity until 30?min at 60°C. The kinetic constants were K_m?=?9.93?mM and V_max?=?2.58 UA min^?1 using p-nitrophenyl palmitate (p-NPP) as substrate. Results showed that Penicillium sp. was able to produce lipase from waste oils using N. cochenillifera, thus having biotechnological potential in waste oil biotransformation.     

Production of a halotolerant lipase from Halomonas sp. strain C2SS100: Optimization by response-surface methodology and application in detergent formulations

The aim of this work was to optimize the production of a new lipase by a halotolerant bacterial strain Halomonas sp. C2SS100, by means of the response-surface methodology (RSM). The process parameters having the most significant effect on lipase production were identified using the Plackett–Burman screening design-of-experiments. Then, Box–Behnken design was applied to optimize lipase activity and the quadratic regression model of the lipase production was built. Indeed, the lipase yield was increased, and the value obtained experimentally (39 ± 2 U/ml) was very close to the rate predicted by the model (40.3 U/ml). Likewise, optimization of parameters by RSM resulted in 2.78-fold increase in lipase activity. These findings provide the first report on lipase production and optimization by a halotolerant bacterial strain belonging to Halomonas genus. Afterward, the biochemical properties of the produced lipase were studied for apply in oil stains removal. The crude lipase showed a maximum activity at 60°C and at pH ranging from 7 to 10. It displayed an important stability at high temperature, pH, and NaCl. Interestingly, this bacterial lipase exhibited a prominent stability toward some commercial solid and liquid detergents after 30 min of incubation at 50°C. The capability of the crude lipase to eliminate stain was ascertained on polycotton fabric pieces stained with lubricating oil. Whether with the addition of hot water alone or of a commercially available detergent, lipase is able to considerably boost the elimination of oil stains. The actual findings highlight the capacity of Halomonas sp. lipase for energy-efficient biocatalytic application.     

Preparation of a promising whole cell biocatalyst of Geotrichum sp. lipase and its properties

BACKGROUND: As a new protein expression and self‐immobilization system, cell‐surface displayed enzymes have attracted increasing attention. In this study, Geotrichum sp. lipase (GSL), an important enzyme for the enrichment of polyunsaturated fatty acids (PUFAs), was first displayed on the cell surface of Saccharomyces cerevisiae. RESULTS: The activity of displayed GSL was higher (43.7 U g^?1 dry cell) than that of Candida antarctica lipase B (26.26 U g^?1 dry cell) and that of Rhizopus oryzae lipase (4.1 U g^?1 dry cell). It also exhibited higher thermostability than the free lipase, and retained 89% of the original activity after incubation at 40 °C for 3 h, compared with 48% at 35 °C for the free lipase at pH 8.5. Interestingly, the displayed lipase had a wider pH range and better pH stability. It had higher activity at all pH values than the free GSL, and retained 86% of the original activity in the pH range 9.5 to 10.5, whereas the activity of the free GSL could not be detected at pH 10. CONCLUSION: This work presented a method to prepare a whole‐cell biocatalyst with better stability and broader pH tolerance which will provide a useful strategy for other cost‐effective self‐immobilized industrial lipases. Copyright © 2011 Society of Chemical Industry     

一株芽孢杆菌的分子鉴定及初步应用条件探究

引言嗜盐菌是生活在高盐环境中的细菌,多生长于盐湖、盐碱湖、死海、盐场和海洋中,腌鱼、咸肉等盐制品上也常有存在。通常嗜盐菌生长在盐浓度大于0.2mol.L-1的环境中[1]。我国西藏、青海     

Reduction of hexavalent chromium by Bacillus sp. isolated from chromite mine soils and characterization of reduced product

BACKGROUND: The reduction of highly mobile and toxic hexavalent chromium by bacterial strains is considered to be a viable alternative to reduce Cr(VI) contamination, in soils and water bodies, emanating from the overburden dumps of chromite ores and mine drainage. The present study reports the isolation of Cr(VI) resistant bacterial strains from an Indian chromite mine soil and their potential use in reduction of hexavalent chromium. RESULTS: Among the isolates, a bacterial strain (CSB‐4) was identified as Bacillus sp. based on standard biochemical tests and partial 16SrRNA gene sequencing, which was tolerant to as high as 2000 mg L^?1 Cr(VI) concentration. The strain was capable of reducing Cr(VI) to Cr(III) in different growth media. Under the optimized conditions pH ～7.0, 100 mg L^?1 Cr(VI), 35 °C temperature and stirring speed 100 rpm, CSB‐4 reduced more than 90% of Cr(VI) in 144 h. The time course reduction data fitted well an exponential rate equation yielding rate constants in the range 3.22 × 10^?2 to 6.5 × 10^?3 h^?1 for Cr(VI) concentration of 10–500 mg L^?1. The activation energy derived from temperature dependence rate constants between 25 and 35 °C was found to be 99 kJ mol^?1. The characterization of reduced product associated with bacterial cells by SEM‐EDS, FT‐IR and XRD was also reported. CONCLUSION: Reasonably high tolerance and reduction ability of indigenous Bacillus sp. (CSB‐4) for Cr(VI) under a wide range of experimental conditions show promise for its possible use in reclamation of chromite ore mine areas including soils and water bodies. Copyright © 2010 Society of Chemical Industry     

Purification and characterization of a lipase fromNeurospora sp. TT-241

An extracellular lipase, which is produced by theNeurospora sp. TT-241 strain, grown on wheat bran at 30°C for 4 d, was purified 370-fold with an overall yield of 16%. The molecular weight was determined to be 55 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimal pH at 30°C and optimal temperature at pH 6.5 were 7 and 45°C, respectively. The lipase was stable in the pH range of 5 to 8, and it was temperature-sensitive. It was active on a wide range of natural substrates of either vegetable or animal origins and towardp-nitrophenyl esters, greatly favoring those containing C₄ acyl groups. It cleaved all of the ester bonds of triolein; however, the 1- or 3-ester bond was the preferred target. A complete inhibition by diisopropyl fluorophosphate suggested the presence of a serine residue at the active site. Partial inhibition was shown by either Hg²⁺ or chloramine T. Enzyme activity persisted in nonionic surfactants, a water-miscible solvent (dimethylsulfoxide), and a water-immiscible solvent (hexane).     

Candida sp.99-125脂肪酶及其在化学品合成中的应用

传统的酯化或转酯化产品的合成通常需要高温、强酸、强碱等相对苛刻的条件,脂肪酶由于其生物催化过程具有高效、高选择性、条件温和和环境友好等特点,在化学品的合成中越来越受到人们的关注。本课题组开发了一种可以用于酯类合成的新脂肪酶,并且实现了该酶的工业化生产。来源于Candida sp. 99-125的脂肪酶在非水相中对酯化和转酯化反应具有高效的催化活性和稳定性。本文介绍了该脂肪酶的发酵生产及其在中长链脂肪酸酯、二元酸酯、维生素A棕榈酸酯、手性化合物以及生物柴油等多种化学品的合成中的应用。     

Expression and characterization of a CALB-type lipase from Sporisorium reilianum SRZ2 and its potential in short-chain flavor ester synthesis

A lipase from Sporisorium reilianum SRZ2 (SRL) with 73% amino acid sequence identity to Candida antarctica lipase B (CALB) was cloned and overexpressed in Pichia pastoris. The recombinant SRL showed a preference for short-chain p-nitrophenyl esters. It achieved maximum activity at pH 8.0 and 65°C for p-nitrophenyl hexanoate (C6) with K_m and k_cat/K_m values of 0.14 mmol∙L⁻¹ and 1712 min⁻¹∙mmol∙L₋₁ at 30°C, respectively. SRL displayed excellent thermostability and pH stability, retaining more than 79% of its initial activity after incubation at 60°C for 72 h and 75% at pH 3 to 11 for 72 h. It also maintained most of its activity in the presence of inhibitors and detergents except sodium dodecyl sulfate, and it tolerated organic solvents. SRL was covalently immobilized and successfully used for ethyl hexanoate synthesis in cyclohexane or in a solvent-free system with a high conversion yield (>95%). Furthermore, high conversion yield was also achieved for the synthesis of various short-chain flavor esters when high substrate concentrations of 2 mol∙L⁻¹ were applied. This study indicated that a CALB-type lipase from S. reilianum SRZ2 showed great potential in organic ester synthesis.     

Production and structural features of a water-soluble polysaccharide from a mutant strain of Agrobacterium sp.

We have developed a mutant strain derived from Agrobacterium sp. ATCC 31750, which produces a water-soluble polysaccharide having potential utility to the food, feed, pharmaceutical and cosmetic industries. A high concentration of product (15 g/L) is obtained by 48 h cultivation of the mutant strain under optimized fermentation conditions. The water-soluble polysaccharide obtained from cultures of the mutant strain beta82 has Glc:Man:Gal in approximate molar ratios of 5.8:6.7:1.0. The molecular weight of the polysaccharide was determined to be approximately 1000 kDa by HPSEC analysis. Linkage analysis contained 3-Glcp, 3-Manp, terminal Glcp and terminal Manp, as well as a small proportion of 3- and 3,4-Galp, and 4,6-Manp residues. Based on analyses using FT-IR and ¹³C NMR spectrometers, most glycosidic bonds joining these sugar residues are of the α-type, and acetyl groups are apparently attached to the polymer chain at random.     

微生物发酵产生苝醌类化合物和甘露醇的工艺研究

目的:研究产生艹北醌类化合物和甘露醇的菌寄生菌属真菌(AscomycetesHypocreaceaeHypomyces(Fr.)Tul.sp.)的发酵工艺。方法:不同固体培养基、温度、固体培养基与水质量比、pH值、氮源、光及碳源对艹北醌类化合物和甘露醇含量的影响。结果:筛选出一条好的发酵工艺。结论:艹北醌类化合物含量提高0.05%～0.1%,甘露醇含量提高0.5%。     

Effect of some leaf essential oil phenotypes from coastal redwood on growth of its predominant endophytic fungus,Pleuroplaconema sp.

Experiments were performed to assess the effect of four foliar essential oil phenotypes from a coastal redwood (Sequoia sempervirens) population on isolates ofPleuroplaconema sp., its ubiquitous endophytic fungus. Isolates were exposed to essential oils extracted from their trees of origin and from other trees. The hypotheses tested were: (1) redwood leaf essential oils extracted from distinct trees would have a differential effect onPleuroplaconema sp. growth, and (2) growth of isolates from a particular tree would be differentially affected when exposed to essential oil phenotypes different from that of their tree of origin. The essential oil phenotypes were differentially inhibitory, but the pattern of inhibition did not support the second hypothesis.Pleuroplaconema sp. showed low average tolerance to all of the essential oils; two phenotypes reduced growth 70–80% and the other two 50–60% at the dose tested. The overall growth response of individual isolates to all treatments suggests that more than one fungus genotype per tree was represented in the experiment. The variability in tolerance of individual isolates to the essential oils was low for three phenotypes. The low tolerance ofPleuroplaconema sp. to redwood essential oils, in spite of its predominance and specialization in this conifer, is discussed considering: (1) the possible pathogenic ancestry of this fungus, and (2) that essential oil phenotypes may be important in controlling the activity ofPleuroplaconema sp. after it colonizes the leaf.