Accounting for Cloud Nucleation Activation Mechanism of Secondary Organic Matter from α-Pinene Oxidation Using Experimentally Retrieved Water Solubility Distributions.

Activation of cloud droplets of aerosol particles from biogenic precursors plays a critical role in Earth's climate system. However, the molecular-level understanding of the cloud condensation nuclei (CCN) activation process for secondary organic matter (SOM) is still lacking. Here, we reduced the gap by segregating SOM from α-pinene based on water solubility. The chemical composition and CCN activity of the solubility-segregated fractions of SOM were measured. The results demonstrated for the first time by laboratory experiment that highly oxygenated compounds such as hydroperoxides and highly oxygenated organic molecules are important contributors for the CCN activity of α-pinene SOM. Meanwhile, relatively less water-soluble species were also abundant. Analysis based on the Köhler theory demonstrated that less water-soluble compounds in SOM remain undissolved during the cloud activation process, suggesting that the traditional single-parameter parameterization for CCN activation would not be sufficient for representing the process. In combination with the recent developments in SOM formation chemistry, the present study helps in understanding the interactions between the biosphere and climate.

Water Solubility Distribution of Organic Matter Accounts for the Discrepancy in Hygroscopicity among Sub- and Supersaturated Humidity Regimes.

Water uptake properties of organic matter (OM) are critical for aerosol direct and indirect effects. OM contains various chemical species that have a wide range of water solubility. However, the role of water solubility on water uptake by OM has poorly been investigated. We experimentally retrieved water solubility distributions of water-soluble OM (WSOM) from combustion of mosquito coil and tropical peat using the 1-octanol-water partitioning method. In addition, hygroscopic growth and cloud condensation nuclei (CCN) activity of solubility-segregated WSOM were measured. The dominant fraction of WSOM from mosquito coil smoldering was highly soluble (water solubility (S) > 10-2 g cm-3), while that from peat combustion contained ∼40% of less-soluble species (S < 10-3 g cm-3). The difference in water solubility distributions induced changes in the roles of less water-soluble fractions (S < 10-3 g cm-3) on CCN activity. Namely, the less water-soluble fraction from mosquito coil combustion fully dissolved at the point of critical supersaturation, while that for tropical peat smoldering was limited by water solubility. The present result suggests that water solubility distributions of OM, rather than its bulk chemical property, need to be quantified for understanding the water uptake process.

A Significant Portion of Water-Soluble Organic Matter in Fresh Biomass Burning Particles Does Not Contribute to Hygroscopic Growth: An Application of Polarity Segregation by 1-Octanol-Water Partitioning Method.

The importance of water-soluble organic matter (WSOM) on the hygroscopic growth of particles is recognized, yet roles of different categories of WSOM are under debate. We segregated WSOM from Indonesian biomass burning particles by the 1-octanol-water partitioning method. The method is based on the 1-octanol-water partition coefficient (KOW), which correlates with water solubility. The segregated WSOM was analyzed using the humidified tandem differential mobility analyzer (HTDMA) and time-of-flight aerosol chemical speciation monitor (ToF-ACSM). Both the hygroscopicity parameter κ and the fractional contribution of m/z 44 (f44), which serves as a metric for degree of oxygenation, increased with polarity. This result experimentally evidenced that highly polar/water-soluble OM is highly hygroscopic/oxygenated. Positive matrix factorization (PMF) identified three factors from the ToF-ACSM data. Deconvolution of κ by PMF factors demonstrated that the less polar fractions, which occupy approximately 20-60% of WSOM dependent on the biomass type, almost do not contribute to water uptake under subsaturated conditions. This result highlights that categorization of WSOM will be needed to understand how hygroscopic growth of aerosol particles is regulated.

Polarity-Dependent Chemical Characteristics of Water-Soluble Organic Matter from Laboratory-Generated Biomass-Burning Revealed by 1-Octanol-Water Partitioning.

Polarity distribution of water-soluble organic matter (WSOM) is an important factor in determining the hygroscopic and cloud nucleation abilities of organic aerosol particles. We applied a novel framework to quantitatively classify WSOM based on the 1-octanol-water partition coefficient (KOW), which often serves as a proxy of polarity. In this study, WSOM was generated in a laboratory biomass-burning experiment by smoldering of Indonesian peat and vegetation samples. The fractionated WSOM was analyzed using a UV-visible spectrophotometer, spectrofluorometer, and time-of-flight aerosol chemical speciation monitor. Several deconvolution methods, including positive matrix factorization, parallel factor analysis, and least-squares analysis, were applied to the measured spectra, resulting in three classes of WSOM. The highly polar fraction of WSOM, which predominantly exists in the range of log KOW < 0, is highly oxygenated and exhibits similar optical properties as those of light-absorbing humic-like substances (HULIS, termed after the humic substances due to the similarity in chemical characteristics). WSOM in the least-polar fraction, which mainly distributes in log KOW > 1, mostly consists of hydrocarbon-like and high molecular weight species. In between the most- and least-polar fraction, WSOM in the marginally polar fraction likely contains aromatic compounds. The analyses have also suggested the existence of HULIS with different polarities. Comparison with previous studies indicates that only WSOM in the highly polar fraction (log KOW < 0) likely contributes to water uptake.

Characterization of the recognition specificity of BH2, a monoclonal antibody prepared against the HLA-B27 heavy chain.

BH2, a monoclonal antibody prepared against the denatured human leukocytic antigen-B27 heavy chain (HLA-B27 HC), can immunoprecipitate the misfolded HLA-B27 HC complexed with Bip in the endoplasmic reticulum and recognize the homodimerized HLA-B27 HC that is often observed on the cell membrane of patients suffered from ankylosing spondylitis (AS). However, the recognition specificity of BH2 toward the other molecules of HLA-B type and toward the different types of HLA molecules remained uncharacterized. In this study, we carried out the HLA-typing by using the Luminex Technology to characterize the recognition specificity of BH2 and analyzed the binding domain of HLA-B27 HC by BH2. Our results indicated that BH2 preferably binds to molecules of HLA-B and -C rather than HLA-A and the binding site is located within the α2 domain of HLA-B27 HC.

Study of Lignin Extracted from Rubberwood Using Microwave Assisted Technology for Fuel Additive.

Lignin is the most abundant natural aromatic polymer, especially in plant biomass. Lignin-derived phenolic compounds can be processed into high-value liquid fuel. This study aimed to determine the yield of lignin by the microwave-assisted solvent extraction method and to characterize some essential properties of the extracted lignin. Rubberwood sawdust (Hevea brasiliensis) was extracted for lignin with an organic-based solvent, either ethanol or isopropanol, in a microwave oven operating at 2450 MHz. Two levels of power of microwave, 100 W and 200 W, were tested as well as five extraction times (5, 10, 15, 20, 25, and 30 min). The extracted lignin was characterized by Klason lignin, Fourier transform infrared spectroscopy (FT-IR), 2D HSQC NMR, Ultraviolet-visible spectrophotometry (UV-vis), and Bomb calorimeter. The results showed that the yield of extracted lignin increased with the extraction time and power of the microwave. In addition, the extraction yield with ethanol was higher than the yield with isopropanol. The highest yield was 6.26 wt.%, with ethanol, 30 min extraction time, and 200 W microwave power.

Production of succinic acid through the fermentation of Actinobacillus succinogenes on the hydrolysate of Napier grass.

BACKGROUND: Napier grass biomass can be hydrolyzed mainly containing glucose and xylose after alkaline pretreatment and enzymatic hydrolysis. This biomass can be fermented using Actinobacillus succinogenes to produce succinic acid. The yield of succinic acid was 0.58 g/g. Because metabolizing xylose could produce more acetic acid, this yield of succinic acid was lower than that achieved using glucose as the sole carbon source. RESULTS: The addition of glycerol as a fermentation substrate to Napier grass hydrolysate increased the reducing power of the hydrolysate, which not only increased the production of succinic acid but also reduced the formation of undesirable acetic acid in bacterial cells. At a hydrolysate:glycerol ratio of 10:1, the succinic acid yield reached 0.65 g/g. The succinic acid yield increased to 0.88 g/g when a 1:1 ratio of hydrolysate:glycerol was used. For the recovery of succinic acid from the fermentation broth, an outside-in module of an ultrafiltration membrane was used to remove bacterial cells. Air sparging at the feed side with a flow rate of 3 L/min increased the filtration rate. When the air flow rate was increased from 0 to 3 L/min, the average filtration rate increased from 25.0 to 45.7 mL/min, which corresponds to an increase of 82.8%. The clarified fermentation broth was then electrodialized to separate succinate from other contaminated ions. After electrodialysis, the acid products were concentrated through water removal, decolorized through treatment with activated carbon, and precipitated to obtain a purified product. CONCLUSIONS: The yield of succinic acid was increased by adding glycerol to the hydrolysate of Napier grass. The downstream processing consisting of ultrafiltration membrane separation and single-stage electrodialysis was effective for product separation and purification. An overall recovery yield of 74.7% ± 4.5% and a purity of 99.4% ± 0.1% were achieved for succinic acid.

Characteristics of Doped TiO2 Nanoparticle Photocatalysts Prepared by the Rotten Egg White.

In this study, expired egg white was used as a template, and a sol-gel method was employed to prepare pure-phase TiO2 nano-powder and mixed-phase powders doped with NaF and NaI. The influences of different calcination temperatures, doping elements, and doping amounts during the preparation process on the photocatalytic performance and activity of the prepared TiO2 powders were studied. The results of the experiments showed that the F-doped TiO2 had the highest photocatalytic activity when the doping amount was 1.2%, as examined by EDS, where the sintering temperature was 500 °C. F-doped TiO2 nanoparticles were also synthesized by the sol-gel method using tetrabutyl titanate and NaF mixed with expired egg white protein as the precursor. The F-TiO2 photocatalyst was characterized using FE-SEM, HR-TEM, EDS, XPS, and UV-Vis, and the photocatalytic activity was evaluated by photodegradation of methylene blue under visible light. The results showed that doping with F reduced the energy band gap (3.04 eV) of TiO2, thereby increasing the photocatalytic activity in the visible-light region. The visible-light wavelength range and photocatalytic activity of the catalyst were also affected by the doping amount.

Covalent binding of glutathione on magnetic nanoparticles: Application for immobilizing small fragment ubiquitin-like-specific protease 1.

Magnetic nanoparticles bound with glutathione (GSH) are useful for diagnostics, enzyme immobilization, and affinity precipitation by using the strong and specific interaction of GSH with glutathione S-transferase (GST)-fused proteins. Our studies revealed that GSH-bound magnetic nanoparticles could be obtained using the covalent bond linkage of GSH and nanoparticles to promote the stability of bound GSH. To yield this conjugate, superparamagnetic iron oxide nanoparticles (SPIONs) were prepared and modified using tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES), which introduced amino groups that were then activated with maleic anhydride (MA) for covalent binding of GSH. After MA was used to activate the amino-grafted SPION for 24 h, the yield of GSH conjugation increased over 4 days from 37 % to 74 % of the original amine density on the surface as the incubation of GSH with MA-activated SPION. These GSH-bound magnetic nanoparticles, designated as SPION@silica-GSH with approximately 103 nmol GSH/mg particles, were ready for coupling with GST-fused protein through the GSH-GST affinity interaction. A GST-tagged small fragment of ubiquitin-like-specific protease 1 (sfULP1) was used as the model protein for immobilization on SPION@silica-GSH. ULP1 is a small ubiquitin-like modifier (SUMO) protease. Results indicated that this immobilized GST-sfULP1 could retain 87 % ± 5 % enzyme activity of free protease before immobilization and could catalyze the cleavage of the SUMO-fused peptide (SUMO-GLP-1) to obtain glucagon-like peptide-1, a peptide hormone for type 2 diabetes therapy.

Protein solubility and differential proteomic profiling of recombinant Escherichia coli overexpressing double-tagged fusion proteins.

BACKGROUND: Overexpression of recombinant proteins usually triggers the induction of heat shock proteins that regulate aggregation and solubility of the overexpressed protein. The two-dimensional gel electrophoresis (2-DE)-mass spectrometry approach was used to profile the proteome of Escherichia coli overexpressing N-acetyl-D-glucosamine 2-epimerase (GlcNAc 2-epimerase) and N-acetyl-D-neuraminic acid aldolase (Neu5Ac aldolase), both fused to glutathione S-transferase (GST) and polyionic peptide (5D or 5R). RESULTS: Overexpression of fusion proteins by IPTG induction caused significant differential expression of numerous cellular proteins; most of these proteins were down-regulated, including enzymes connected to the pentose phosphate pathway and the enzyme LuxS that could lead to an inhibition of tRNA synthesis. Interestingly, when plasmid-harboring cells were cultured in LB medium, gluconeogenesis occurred mainly through MaeB, while in the host strain, gluconeogenesis occurred by a different pathway (by Mdh and PckA). Significant up-regulation of the chaperones ClpB, HslU and GroEL and high-level expression of two protective small heat shock proteins (IbpA and IbpB) were found in cells overexpressing GST-GlcNAc 2-epimerase-5D but not in GST-Neu5Ac aldolase-5R-expressing E. coli. Although most of the recombinant protein was present in insoluble aggregates, the soluble fraction of GST-GlcNAc 2-epimerase-5D was higher than that of GST-Neu5Ac aldolase-5R. Also, in cells overexpressing recombinant GST-GlcNAc 2-epimerase-5D, the expression of σ32 was maintained at a higher level following induction. CONCLUSIONS: Differential expression of metabolically functional proteins, especially those in the gluconeogenesis pathway, was found between host and recombinant cells. Also, the expression patterns of chaperones/heat shock proteins differed among the plasmid-harboring bacteria in response to overproduction of recombinant proteins. In conclusion, the solubility of overexpressed recombinant proteins could be enhanced by maintaining the expression of σ32, a bacterial heat shock transcription factor, at higher levels during overproduction.

Cellular uptake of protein-bound magnetic nanoparticles in pulsed magnetic field.

A method for fast delivery of proteins conjugated to superparamagnetic iron oxide nanoparticles (SPION) into mammalian cells by applying a strong magnetic field in pulses was proposed. Firstly, SPION were prepared from an alkaline solution of divalent and trivalent iron ions and covalently bound with protein through the activation of N-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC). After fluorescently labelling, the protein-nanoparticle conjugate was mixed with mammalian cell line and exposed to a pulsed magnetic field for short durations of few milliseconds. Results suggested that superparamagnetic nanoparticles were able to carry proteins into living cells immediately. Cellular internalization of the fluorescently labelled protein-nanoparticle conjugate was proved by the observation of cell fluorescence in a fluorescent microscopy, as well as cell analysis by a flow cytometer. We found that the cellular uptake was accomplished dominantly by the process of bombardment of magnetic nanoparticles.

Proteomic changes in the hypothalamus and retroperitoneal fat from male F344 rats subjected to repeated light-dark shifts.

Chronic circadian desynchronization induced by repeated 12 h light-dark cycle shifts conducted twice weekly resulted in elevated food intake, body weight gain, and retroperitoneal fat mass in male F344 rats. Using a proteomic approach, we found that repeated light-dark shifts caused changes in expression levels of five hypothalamic (four upregulated) and 22 retroperitoneal fat (13 upregulated) 2-DE protein spots. Proteins involved in carbohydrate metabolism and in the citric acid cycle were upregulated, indicating a positive energy balance status. In addition, the hypothalamic gamma-amino butyric acid (GABA) aminotransferase was upregulated, thus suggesting a connection between the brain GABAeric system and the modulation of food intake. Furthermore, the upregulation of fatty acid-binding protein 4 and the downregulation of 78 kDa glucose-regulated protein in the fat implicated the development of insulin resistance. We observed the upregulation of two antioxidant enzymes that might serve as protection against insulin dysfunction associated with oxidative stress. Finally, the downregulation of hypothalamic voltage-dependent anion-selective channel protein 1 and fat ATP synthase suggested a reduction in synthesis of mitochondrial ATP. These findings are in partial agreement with those of studies of obesity induced by genotype and a high-fat diet.

Production of N-acetyl-D-neuraminic acid using two sequential enzymes overexpressed as double-tagged fusion proteins.

BACKGROUND: Two sequential enzymes in the production of sialic acids, N-acetyl-D-glucosamine 2-epimerase (GlcNAc 2-epimerase) and N-acetyl-D-neuraminic acid aldolase (Neu5Ac aldolase), were overexpressed as double-tagged gene fusions. Both were tagged with glutathione S-transferase (GST) at the N-terminus, but at the C-terminus, one was tagged with five contiguous aspartate residues (5D), and the other with five contiguous arginine residues (5R). RESULTS: Both fusion proteins were overexpressed in Escherichia coli and retained enzymatic activity. The fusions were designed so their surfaces were charged under enzyme reaction conditions, which allowed isolation and immobilization in a single step, through a simple capture with either an anionic or a cationic exchanger (Sepharose Q or Sepharose SP) that electrostatically bound the 5D or 5R tag. The introduction of double tags only marginally altered the affinity of the enzymes for their substrates, and the double-tagged proteins were enzymatically active in both soluble and immobilized forms. Combined use of the fusion proteins led to the production of N-acetyl-D-neuraminic acid (Neu5Ac) from N-acetyl-D-glucosamine (GlcNAc). CONCLUSION: Double-tagged gene fusions were overexpressed to yield two enzymes that perform sequential steps in sialic acid synthesis. The proteins were easily immobilized via ionic tags onto ionic exchange resins and could thus be purified by direct capture from crude protein extracts. The immobilized, double-tagged proteins were effective for one-pot enzymatic production of sialic acid.

Fast transfection of mammalian cells using superparamagnetic nanoparticles under strong magnetic field.

Through the use of superparamagnetic iron oxide nanoparticles (SPIONs), fast delivery of DNA into adherent and suspended cells could be achieved by the mediation of a strong impulsed magnetic field. Mammalian cells were well transfected with enhanced green fluorescent protein gene. To mediate the cellular uptake, cells and nucleic acid complexes were mixed together and exposed once or several times to impulsed magnetic field for short durations of few milliseconds. In the transfection of adherent cells, most complexes of plasmid DNA and polyethylenimine (PEI)-coated SPIONs were internalized immediately. In comparison with no magnetic pulsing, the enhancement in transfection efficiency was about two fold on average by pulsing in magnetic field of 0.6 Tesla three times. The transfection yield increased with the strength of magnetic field and the number of pulsing. Disregarding the cytotocixity of internalized PEI, the loss of cell viability by magnetic pulsing was not evidenced.

Differentially expressed serum haptoglobin alpha chain isoforms with potential application for diagnosis of head and neck cancer.

BACKGROUND: The discovery of molecular biomarkers is crucial to the diagnosis of head and neck squamous cell cancer (HNSCC). METHODS: Proteins from pre-surgery serum samples of patients with HNSCC and healthy individuals were analyzed by 2-dimensional gel electrophoresis (2-DE) using a 17 cm-long immobilized pH gradient gel strip (large gel). The differentially expressed protein spots were detected by statistical analysis. Because 2 haptoglobin (Hp) alpha chains were found to be differentially expressed, the genotypic distribution of Hp alpha chains in patients and healthy individuals was assayed by polymerase chain reaction. The protein expression levels of Hp alpha chains in individuals carrying different Hp alleles were analyzed by 2-DE with a small gel. RESULTS: Two isoforms of haptoglobin alpha2 chain (Hp alpha2) in patients' sera were found from 2-DE analysis to be up-regulated, while the isoforms of haptoglobin alpha1 chain (Hp alpha1) were significantly down-regulated. Apolipoprotein AII and 2 isoforms of apolipoprotein CII were also differentially expressed in the sera of patients with HNSCC. The Hp alpha2 chain was significantly up-regulated in the patients carrying at least one haptoglobin 2 allele, according to the spot intensities from scanned images of small-gel 2-DE. CONCLUSIONS: The expression pattern of seven differentially expressed polypeptides and the up-regulation of Hp alpha2 in individuals with the Hp 2 allele are potential biomarkers.

Chromatographic characterization of molecularly imprinted polymers.

Recent efforts in the investigation of chromatographic characterization of molecularly imprinted polymers (MIPs) have focused mainly on the nature of heterogeneous binding sites. More data on the thermodynamics than on the kinetic features of MIP columns have been published. The present article addresses the sources of peak broadening and tailing, which are the main drawbacks often associated with imprinted polymers in chromatography for practical applications. With use of the theory of nonlinear chromatography, the peak properties of a MIP column, including the retention and peak broadening and tailing, can be well interpreted. Efforts to improve chromatographic efficiency using MIPs prepared by approaches different from the conventional method, including covalent imprinting and the format of uniformly sized spherical microbeads, are reviewed and discussed. This review leads to the conclusion that nonlinear chromatography theory is useful for characterizing chromatographic features of MIP columns, since a MIP is essentially an affinity-based chromatographic stationary phase. We expect more theoretical and experimental studies on the kinetic aspects of MIP columns, especially the factors influencing the apparent rate constant, as well as the analysis of the influences of mobile-phase composition on the chromatographic performance. In addition to revealing the affinity interaction by molecular recognition, slow nonspecific interactions which may be inherited from the imperfect imprinting and may be involved in the rebinding of the template to MIPs also need to be characterized.

Model of acetic acid-affected growth and poly(3-hydroxybutyrate) production by Cupriavidus necator DSM 545.

Acetic acid, a potential growth inhibitor, commonly occurs in lignocellulosic hydrolysates. The growth of Cupriavidus necator DSM 545 and production of poly(3-hydroxybutyrate) (PHB) by this bacterium in a glucose-based medium supplemented with various initial concentrations of acetic acid are reported. The bacterium could use both glucose and acetic acid to grow and produce PHB, but acetic acid inhibited growth once its initial concentration exceeded 0.5 g/L. As acetic acid is an unavoidable contaminant in hydrolysates used as sugar sources in commercial fermentations, a mathematical model was developed to describe its impact on growth and the production of PHB. The model was shown to satisfactorily apply to growth and PHB production data obtained in media made with acetic-acid-containing hydrolysates of Napier grass and oil palm trunk as carbon substrates.

Characterization of plasma proteome in biliary atresia.

BACKGROUND: Biliary atresia (BA) is a disorder during infancy with unknown etiology in which progression frequently leads to liver cirrhosis. Plasma proteome is characterized in this study. METHODS: Twelve paired plasma samples from 6 children with BA who received surgical correction at early stage and then liver transplantation at late stage of liver cirrhosis were studied. Plasma samples from 2 subjects without liver disorder were used as normal reference for 2-dimensional gel electrophoresis and for identification of protein spots by mass spectrometric analysis. Plasma samples from another 3 normal subjects (with a total of 5) were used for nephelometric quantification of immunoglobulin kappa light chain in comparison with patients' samples. RESULTS: Among the protein spots detected, ranging from 6 to 200 kDa mass with pIs of 3-10, significant up-regulation of immunoglobulin kappa light chain was found at the late stage of BA, which was subsequently confirmed by nephelometric analysis. Conversely, significant decrease of apolipoprotein (Apo) A-I and C-II, haptoglobin alpha2 and beta chain, and transthyretin were detected during the progression of BA. CONCLUSIONS: Increased immunoglobulin kappa light chain detected in late-stage BA characterizes adverse immune modulation in this disorder. Decreased apolipoproteins, haptoglobin and transthyretin levels might be potential markers of progressive liver injury, fibrosis and defective lipid metabolism in BA.

Furfural and glucose can enhance conversion of xylose to xylitol by Candida magnoliae TISTR 5663.

Xylitol production from xylose by the yeast Candida magnoliae TISTR 5663 was enhanced by supplementing the fermentation medium with furfural (300mg/L) and glucose (3g/L with an initial mass ratio of glucose to xylose of 1:10) together under oxygen limiting conditions. In the presence of furfural and glucose, the final concentration of xylitol was unaffected relative to control cultures but the xylitol yield on xylose increased by about 5%. Supplementation of the culture medium with glucose alone at an initial concentration of 3g/L, stimulated the volumetric and specific rates of xylose consumption and the rate of xylitol production from xylose. In a culture medium containing 30g/L xylose, 300mg/L furfural and 3g/L glucose, the volumetric production rate of xylitol was 1.04g/L h and the specific production rate was 0.169g/g h. In the absence of furfural and glucose, the volumetric production rate of xylitol was ∼35% lower and the specific production rate was nearly 30% lower. In view of these results, xylose-containing lignocellulosic hydrolysates contaminated with furfural can be effectively used for producing xylitol by fermentation so long as the glucose-to-xylose mass ratio in the hydrolysate does not exceed 1:10 and the furfural concentration is ≤300mg/L.

Amylolytic Enzymes Acquired from L-Lactic Acid Producing Enterococcus faecium K-1 and Improvement of Direct Lactic Acid Production from Cassava Starch.

An amylolytic lactic acid bacterium isolate K-1 was isolated from the wastewater of a cassava starch manufacturing factory and identified as Entercoccus faecium based on 16S rRNA gene sequence analysis. An extracellular α-amylase was purified to homogeneity and the molecular weight of the purified enzyme was approximately 112 kDa with optimal pH value and temperature measured of 7.0 and 40 °C, respectively. It was stable at a pH range of 6.0-7.0, but was markedly sensitive to high temperatures and low pH conditions, even at a pH value of 5. Ba2+, Al3+, and Co2+ activated enzyme activity. This bacterium was capable of producing 99.2% high optically pure L-lactic acid of 4.3 and 8.2 g/L under uncontrolled and controlled pH at 6.5 conditions, respectively, in the MRS broth containing 10 g/L cassava starch as the sole carbon source when cultivated at 37 °C for 48 h. A control pH condition of 6.5 improved and stabilized the yield of L-lactic acid production directly from starch even at a high concentration of starch at up to 150 g/L. This paper is the first report describing the properties of purified α-amylase from E. faecium. Additionally, pullulanase and cyclodextrinase activities were also firstly recorded from E. faecium K-1.