Mycoflora of Crude Oil Polluted Soils of Ukwa West of Abia State Nigeria

Aim: Bioremediation of soil play a critical role in removing pollutants from crude oil polluted soil. To investigate the mycoflora of crude oil polluted area of Ukwa West Local Government in the present Abia State. Methodology: Portions of the soil samples collected from three (3) locations were plated out separately on Yeast Starch Agar, Starch Agar, and Cellulose Agar using soil plate methods. The culture plates were examined after 5-7 and 14 days for the presence of fungi. Pure cultures of the isolates were obtained by subculturing and the physico-chemical properties of the soil samples were determined using standard methods. Results: Twenty species (20) of fungi were isolated from the crude oil polluted soil sample and represented by their respective genera. Eight (8) species of Aspergillus representing 40%, two (2) species of Thermomyces representing 10% each, and one (1) species of Penicillium, Cladosporium, Cunninghamella, Curvularia, Trichoderma, Scopulariopsis, Sporotrichum and Basipetospora representing 5% each. Aspergillus species were predominant which include among others A. fumigatus, A. niger, A. parasiticus, A. oryzae, A. terreus. The physico-chemical properties of the soil sample were found to be varied and have affected the distribution and population of fungi. The pH values ranged from 4.81- 5.58 as compared to the control ranging from 5.72- 6.50 for soil samples A, B and C. The moisture content values ranged between 26.46-29.59% as compared to the control ranging from 29.41-32.51%. The soil was found to be high in organic matter content with values of 70.3-82.7% as compared to the control which was 94% for each of the locations. Conclusion: Crude oil polluted soils of Ukwa West of Abia State, Nigeria is rich in fungal biodiversity with the soil’s samples having different physico-chemical properties.

Plasticized Starch/Agar Composite Films: Processing, Morphology, Structure, Mechanical Properties and Surface Hydrophilicity

Natural biopolymers, which are renewable, widely available, biodegradable, and biocompatible, have attracted huge interest in the development of biocomposite materials. Herein, formulation–property relationships for starch/agar composite films were investigated. First, rapid visco analysis was used to confirm the conditions needed for their gelation and to prepare filmogenic solutions. All the original crystalline and/or lamellar structures of starch and agar were destroyed, and films with cohesive and compact structures were formed, as shown by SEM, XRD, and SAXS. All the plasticized films were predominantly amorphous, and the polymorphs of the composite films were closer to that of the agar-only film. FTIR results suggest that the incorporation of agar restricted starch chain interaction and rearrangement. The addition of agar to starch increased both tensile strength and elongation at break, but the improvements were insignificant after the agar content was over 50 wt.%. Contact angle results indicate that compared with the other samples, the 4:6 (wt./wt.) starch/agar film was less hydrophilic. Thus, this work shows that agar dominates the structure and properties of starch/agar composites, and the best properties can be obtained with a certain starch/agar ratio. Such composite polysaccharide films with tailored mechanical properties and surface hydrophilicity could be useful in biodegradable packaging and biomedical applications (wound dressing and tissue scaffolding).

ISOLASI BAKTERI AMILOLITIK DARI RAGI

Penelitian ini bertujuan untuk mendapatkan bakteri amilolitik dan untuk mengetahui aktifitas amilase. Uji aktifitas kualitatif amilase menggunakan media SSA. Hasil isolasi bakteri yang diisolasi dari ragi tape berjumlah 7 isolat. Kemudian 7 isolat bakteri diberi kode: a, b, c, d, e, f dan j. Tujuh isolat dilakukan seleksi astau skrining dengan menumbuhkan pada medium Soluble Starch Agar (SSA). Hasil seleksi diperoleh 4 isolat yang menunjukkan adanya aktifitas amilase ektraseluler. Aktifitas enzim tertinggi terdapat pada isolat j yang memiliki indeks zona bening koloni sebesar 12. Setiap kinerja enzim dipengaruhi oleh keadaan lingkungan seperti pH dan suhu. Enzim mempunyai konstanta disosiasi pada gugus asam maupun gugus basanya, terutama pada gugus residu terminal karboksil dan gugus terminal aminonya. Peningkatan aktifitas enzim dapat disebabkan oleh terjadinya perubahan ionisasi enzim, substrat atau kompleks enzim substrat.

Molecular characterization of gene encoding halo tolerant amylase of Bacillus paralicheniformis isolated from Jazan region

Objectives: This study aims to characterize the gene encoding halo tolerant amylase of bacteria isolated from Jazan region. Materials and Methods: Soil samples were collected from several area of Jazan region, KSA. The samples were serially diluted and plateted on starch agar plates. The amylase producing bacteria were detected by iodine test. To determine the halophilic amylase producing bacteria, several colonies were tested for their ability to grow at higher concentrations of NaCl ranging from 7 to 16%. The bacteria was identified by 16S rRNA and the full length amylase gene was fully identified by sequencing using specific primers. Results: One bacterial halophilic isolate was able to grow on starch agar medium up to 14% NaCl. The Gram stain of the isolate indicated that it is Gram-positive, bacilli. The 16S rRNA gene homology study showed that the bacterial isolate was identified as Bacillus paralicheniformis. Two specific primers were designed named S1F, S1R, to amplify the amylase gene (AMY) region using PCR and the PCR product was sequenced. The sequencing results showed that the full-length amy gene of B. paralicheniformis was of 1452 encoding 483 amino acids. The expected M.Wt. of the protein expressed is of 55 KDa. Conclusion: We report the isolation, identification, and characterization of an isolate of halophilic bacterium isolated from Jazan region. Based on molecular identification, this isolate was identified as Bacillus paralicheniformis. This bacterial strain has an α-amylase gene in its genome and is able to produce extracellular α-amylase. Based on the findings of this work we propose that Bacillus paralicheniformis amy gene could be cloned into expression vector for large scale production.