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Applied Biochemistry and Biotechnology: Part A: Enzyme Engineering and Biotechnology (v.120, #3)

Biotechnological storage and utilization of entrapped solar energy by Sumana Bhattacharya; Marc Schiavone; Amiya Nayak; Sanjoy K. Bhattacharya (pp. 159-167).

Our laboratory has recently developed a device employing immobilized F₀F₁ adenosine triphosphatase (ATPase) that allows synthesis of adenosine triphosphate (ATP) from adenosine 5′-diphosphate and inorganic phosphate using solar energy. We present estimates of total solar energy received by Earth’s land area and demonstrate that its efficient capture may allow conversion of solar energy and storage into bonds of biochemicals using devices harboring either immobilized ATPase or NADH dehydrogenase. Capture and storage of solar energy into biochemicals may also enable fixation of CO₂ emanating from polluting units. The cofactors ATP and NADH synthesized using solar energy could be used for regeneration of acceptor d-ribulose-1,5-bisphosphate from 3-phosphoglycerate formed during CO₂ fixation.

Keywords: Solar energy; F₀F₁ adenosine triphosphatase; immobilization; land area; CO₂ fixation

Glycine-rich proteins by Amir Mousavi; Yasuo Hotta (pp. 169-174).

Glycine-rich proteins (GRPs) containing more than 60% glycine have been found in different tissues from many eukaryotic species. Despite the availability of literature on different groups of GRPs, there are few reports in which they are all considered and compared together. Some of these proteins are components of the cell walls of many higher plants. In most cases, it has been shown that they are accumulated in the vascular tissues and that their synthesis is part of the plant’s defense mechanism. Other distinct types of GRPs are characterized by having structures and functions similar to animal cytokeratins or by a domain with typical RNA-binding motifs. The availability of cloned GRP genes facilitates the study of the function of this diverse class of proteins, which is expected to enhance the understanding of cell physiology.

Keywords: Cell wall proteins; cytokeratin-like proteins; glycine-rich protein (GRP); stress response; RNA-binding proteins

Biodegradation of bisphenol a by fungi by Wen Chai; Yuichi Handa; Masako Suzuki; Michihiko Saito; Nakahide Kato; C. Akira Horiuchi (pp. 175-182).

The biologic degradation of 2,2-bis(4-hydroxyphenyl)propane (bisphenol A [BPA]; 1) was studied with 26 fungi. An initial BPA concentration of 40 ppm in an aqueous solution was degraded in the dark for 14 d. Among the 26 strains tested, 11 degraded BPA at 50% or more. Furthermore, four strains (F. sporotrichioides NFRI-1012, F. moniliforme 2–2, A. terreus MT-13, and E. nidulans MT-98) were more effective for degradation of BPA.

Keywords: Bisphenol A; endocrine disrupter; fungi; biologic degradation; spores

Construction and evaluation of nagR-nagAa::lux fusion strains in biosensing for salicylic acid derivatives by Robert J. Mitchell; Man Bock Gu (pp. 183-197).

The NagR protein is a response regulatory protein found in the bacterium Ralstonia sp. U2 that is involved in sensing for salicylic acid and the subsequent induction of the operaon just upstream of its gene. The genes encoded for in this operon are involved in the degradation of salicylic acid. Escherichia coli strain RFM443 carrying a fusion of the Photorhabdus luminesscens luxCDABE operon with the nagR gene and upstream region of the nagAa gene was constructed and characterized with respect to its optimum temperature, its response time and kinetics, and its ability to deterctnumerous benzoic acid derivatives. Although capable of detecting 0.5 mM salicylic acid at any temperature between 28 and 40°C, this E. coli strain, labeled DNT5, showed its greatest relative activity at 30°C, i.e., the temperature at which the largest induction was seen. Furthermore, experiments done with numerous benzoic acid derivatives found the NagR protein to be responsive to only a few of the compounds tested, including salicylic acid and 3-methyl salicylic acid and 3-methyl saliyclic acid, and acetyl salicylic acid was the strongest inducer. The lower limits of detection for these compounds with E. coli strain DNT5 were also established, wit the native inducer, salicylic acid, giving the most sensitive response and detectable down to a concentration of about 2 μM. A second lux fusion plasmid was also constructed and transformed into an NahR background, Pseudomonas putida KCTC1768. Within this strain, NAGK-1768, the supplemental activity of the NahR protein on the nagAn promoter, was shown to extend both the range of chemicals detected and the sensitivity.

Keywords: Bacterial biosensor; bioluminescence; NahR; naph thalene; salicylic acid

Desulfurization of dibenzothiophene, benzothiophene, and other thiophene analogs by a newly isolated bacterium, Gordonia alkanivorans strain 1B by Luís Alves; Rita Salgueiro; Carla Rodrigues; Elsa Mesquita; José Matos; Francisco M. Gírio (pp. 199-208).

A novel bacterium, Gordonia alkanivorans strain 1B, was isolated from hydrocarbon-contaminated soil. Assessment of the biodegradation of distinct organic sulfur-compounds, such as dibenzothiophene (DBT), benzothiophene (BT), DBT sulfone, and alkylated tiophenic compounds, as the sole source of sulfure was investigated. G. alkanivorans strain 1B was able to remove selectively the sulfur from DBT while keeping intact the remaining carbon-carbon structure. Orthophenyl phenol (2-hydroxybiphenyl) was the only detected metabolic product. The bacterial desulfurization activity was repressed by sulfate. G. alkanivorans straini 1B consumed 310 μM DBT after 120 h of cultivation, corresponding to a specific desulfurization rate of 1.03 μmol/(g of dry cells·h). When an equimolar mixture of DBT/BT was used as a source of sulfur in the growth medium, G. alkanivorans strain 1B assimilated both compounds in a sequential manner, with BT as the preferred source of sulfur. Only when BT concentration was decreased to a very low level was DBT utilized as the source of sulfur for bacterial growth. Thespecific desulfurization overall rates of BT and DBT obtained were 0.954 and 0.813 μmol/(g of dry cells·h), respectively. The newly isolated G. alkanivorans strain 1B has good potential for application in the biodesulfurization of fossil fuels.

Keywords: Biodeusulfurization; dibenzothiophene; benzothiophene; sulfur; Gordonia alkanivorans

General characterization of noncommercial microbial lipases in hydrolytic and synthetic reactions by C. Otero; M. A. Berrendero; F. Cardenas; E. Alvarez; S. W. Elson (pp. 209-223).

Fourteen noncommercial preparations of microbial lipases were investigated with respect to their catalytic activity for hydrolysis and synthesis of ester bonds. Six of the lipases were derived from microorganisms that have not previously been described as lipase producers, and another four were characterized for the first time. The synthetic reactions were carried out in two solvents of different polarities (n-heptane and acetone) using a series of fatty acids and primary and secondary alcohols with different chain lengths. Under the culture conditions employed, Pseudomonas cepacia produced more active enzyme than the other microorganisms. The lipase preparations produced using Ovadendron sulphureo-ochraceum, Monascus mucoroides, Monascus sp., Fusarium oxysporum, Penicillium chrysogenum, Rhodotorula araucariae, Pseudomonas cepacia, Streptomyces halstedii, and Streptomyces sp. were the most efficient catalysts for hydrolysis at lipid-water interfaces. Enzyme preparations from P. cepacia, Streptomyces sp., S. halstedii, and R. araucariae were good biocatalysts for esterification in the polar medium (acetone). When the lipase preparations with the greatest activity for hydrolytic, reactions were excluded, regression analysis of the data for the hydrolytic and synthetic activities of the remaining lipase preparations yielded high multiple correllation coefficients for these reactions in both n-heptane and acetone (R=0.82 and 0.91, respectively).

Keywords: Lipases; esterases; hydrolysis; synthesis; esterification; triacylglycerols; Pseudomonas ; Candida ; Streptomyces

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Applied Biochemistry and Biotechnology: Part A: Enzyme Engineering and Biotechnology (v.120, #3)

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Applied Biochemistry and Biotechnology: Part A: Enzyme Engineering and Biotechnology (v.120, #3)