This paper investigates a severe microbiologically influenced failure in the elbows of a buried amine pipeline in a petrochemical plant. Pipelines can experience different corrosion mechanisms, including microbiologically influenced corrosion (MIC). MIC, a form of biodeterioration initiated by microorganisms, can have a devastating impact on the reliability and lifetime of buried installations. This paper provides a systematic investigation of a severe MIC-related failure in a buried amine pipeline and includes a detailed microstructural analysis, corrosion products/biofilm analyses, and monitoring of the presence of causative microorganisms. Conclusions were drawn based on experimental data, obtained from visual observations, optical/electron microscopy, and Energy-dispersive X-ray spectroscopy (EDS)/X-Ray Diffraction (XRD) analyses. Additionally, monitoring the presence of causative microorganisms, especially sulfate-reducing bacteria which play the main role in corrosion, was performed. The results confirmed that the failure, in this case, is attributable to sulfate-reducing bacteria (SRB), which is a long-known key group of microorganisms when it comes to microbial corrosion.

Tyrosinases, copper-containing monooxygenases, are widely used enzymes for industrial, medical, and environmental applications. We report the first functional surface display of Bacillus megaterium tyrosinase on Bacillus subtilis spores using CotE as an anchor protein. Flow Cytometry was used to verify surface expression of tyrosinase on the purified spores. Moreover, tyrosinase activity of the displayed enzyme on B. subtilis spores was monitored in the presence of L-tyrosine (substrate) and CuSO (inducer). The stability of the spore-displayed tyrosinase was then evaluated after 15 days maintenance of the spores at room temperature, and no significant decrease in the enzyme activity was observed. In addition, the tyrosinase-expressing spores could be repeatedly used with 62% retained enzymatic activity after six times washing with Tris-HCl buffer. This genetically immobilized tyrosinase on the spores would make a new advance in industrial, medical, and environmental applications.

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Pectin, a diverse carbohydrate polymer in plants consists of a core of α-1,4-linked D-galacturonic acid units, includes a vast portion of fruit and agricultural wastes. Using the wastes to produce beneficial compounds is a new approach to control the negative environmental impacts of the accumulated wastes. In the present study, we report a pectinase producing bacterium Streptomyces hydrogenans YAM1 and evaluate antioxidative and anticancer effects of the oligosaccharides obtained from pectin degradation. The production of oligosaccharides due to pectinase activity was detected by thin layer chromatography (TLC) and matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS). Our results revealed that S. hydrogenans YAM1 can degrade pectin to unsaturated pectic oligo-galacturonic acids (POS) with approximately 93% radical scavenging activity in 20 mg/mL which it is more than 50% of the same concentration of pectin. Flow cytometric analysis revealed that MCF-7 cells viability decreased more than 32 and 92% following treatment with 6 and 20 mg/mL POS after 24 h, respectively. It is suggested that pectin degradation by S. hydrogenans YAM1 is not only a new approach to produce highly active compounds from fruit wastes, but also is an effective method to remove fibrous pollutants from different environments.

In this paper, we report removing heavy metal using Bacillus subtilis spore surface display system. We used CotE protein as an anchoring motif because of its high abundance and location in the outer coat layer. And we inserted His 12 (double histidine 6 tag) at the C-terminal end of anchoring motif. The proper expression of CotE-His 12 fusion protein (22.8 kDa) was confirmed by western blot. We confirmed the surface expression of the CotE-His 12 fusion protein using flow cytometry. We tried Ni 2+ and Cd 2+ adsorption with recombinant spore DB104 (pCotE-His 12) and DB104 spore. The amount of adsorbed Ni 2+ was 18.2 nmol/mg for DB104 spore and 82.4 nmol/mg for DB104 (pCotE-His 12) spore. In the case of Cd 2+ , the adsorbed amount was 32.6 nmol/mg for DB104 spore and 79.1 nmol/mg for DB104 (pCotE-His 12) spore. This means that our spore displayed His 12 system can be generally applied for the removal of various kind of heavy metals in the field.

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