Characterization of novel cellulase and glucose isomerase-producing bacteria and optimization of the enzyme production conditions and their potential applications in environment and industry

Cellulases and glucose isomerases are vital enzymes in converting cellulose into fructose. Cellulases catalyze cellulose conversion to glucose, while glucose isomerase catalyzes the reversible isomerization of glucose to fructose. There is a growing interest lately in producing bio-based chemicals and materials from fructose. Soil bacteria produce these enzymes. The characterization of bacteria for enzyme saccharification of biomass is essential for fructose production and reducing the time and cost of current bioconversion processes. From this perspective, we characterized novel cellulase and glucose isomerase-producing bacteria from soil samples and optimize their enzyme production. Coculturing and whole-cell immobilization for glucose isomerase and bacterial resistance to environmental factors were also investigated. Six bacterial strains, Paenarthrobacter sp. MKAL1, Hymenobacter sp. MKAL2, Mycobacterium sp. MKAL3, Stenotrophomonas sp. MKAL4, Chryseobacterium sp. MKAL5 and Bacillus sp. MKAL6 were isolated from mixture soil samples collected at Kingfisher Lake and the University of Manitoba campus and identified using 16S rRNA gene sequence analysis. Using plate assay techniques, these strains were selected for cellulase and glucose isomerase production based on the clearance zone appearance. These strains displayed various morphological and biochemical characteristics. [...

Antibacterial and Antioxidant Properties of the Methanolic Extract of the Stem Bark of Pteleopsis hylodendron (Combretaceae)

Pteleopsis hylodendron (Combretaceae) is used in Cameroon and West Africa folk medicine for the treatment of various microbial infections (measles, chickenpox, and sexually transmitted diseases). The antibacterial properties of the methanolic extract and fractions from stem bark of Pteleopsis hylodendron were tested against three Gram-positive bacteria and eight Gram-negative bacteria using Agar-well diffusion and Broth microdilution methods. Antioxidant activities of the crude extract and fractions were investigated by DPPH radical scavenging activity and β-carotene-linoleic acid assays. The methanolic extract and some fractions exhibited antibacterial activities that varied between the bacterial species (ID = 0.00–25.00 mm; MIC = 781–12500 μg/mL and 0.24–1000 μg/mL). The activity of the crude extract is, however, very weak compared to the reference antibiotics (MIC = 0.125–128 μg/mL). Two fractions (FE and FF) showed significant activity (MIC = 0.97 μg/mL) while S. aureus ATCC 25922 was almost resistant to all the tested fractions. In addition, the crude extract and some fractions showed good antioxidant potential with inhibition values ranging from 17.53 to 98.79%. These results provide promising baseline information for the potential use of this plant as well as some of the fractions in the treatment of infectious diseases and oxidative stress

Screening and Molecular Identification of Novel Pectinolytic Bacteria from Forest Soil

Pectinases are a group of enzymes with broad application, including in plant fiber processing, pectic wastewater treatment, paper pulping, fruit juice extraction, and clarification. With an increasing industrial demand for these enzymes, it is useful to isolate organisms that produce large amounts of pectinase and possess wide ranges of stability factors like temperature and pH. In this study, 17 out of 29 bacteria (58.62%) from forest soil samples were pectinolytic. However, only four bacteria (S-5, S-10, S-14, and S-17) showed high pectin hydrolysis zones (ranging from 0.2 cm to 1.7 cm). These four bacteria were identified based on colony morphology, microscopic characterization, biochemical characteristics, and 16S rDNA sequencing. They were designated as Streptomyces sp. (S-5, S-14), Cellulomonas sp. (S-10), and Bacillus sp. (S-17). Interestingly, bacteria showed cellulase and xylanase activity in addition to pectinase. The quantitative assay for pectinase activity of the four isolates provided proof that they are pectinase producers and can be considered potential candidates for industrial uses. The crude enzyme extracts of these bacteria are applicable in oil and juice extraction from sesame seeds and apples, respectively

Antimycobacterial potency and cytotoxicity study of three medicinal plants

Objective/Background: Mycobacterial infections including tuberculosis, leprosy, and buruli ulcer are among the most prevalent, debilitating, and deadly tropical diseases, especially in Sub-Saharan Africa. The development of drug resistance to the currently available drugs and the poor compliance emphasize the need for new chemotherapeutic agents. This study was designed to evaluate the in vitro activity of Cleistopholis patens, Annona reticulata, and Greenwayodendron suaveolens against Mycobacterium smegmatis. The safety on normal liver cells was also assessed. Methods: The crude extracts, fractions, and subfractions were tested against M. smegmatis and for cell cytotoxicity on WRL-68, normal human hepatocyte using microdilution resazurin-based assays. The phytochemical screening was performed using standard methods. Results: Most of the extracts, fractions, and subfractions inhibited the growth of M. smegmatis with minimum inhibitory concentration (MIC) values ranging from 6.25 μg/mL to 125 μg/mL. The subfractions P12 and P29 from G. suaveolens twig were more potent with MIC values of 6.25 μg/mL and 25 μg/mL, respectively. Fruit crude extract and root CH2Cl2 fraction from A. reticulata also showed activity with MIC values of 50 μg/mL and 25 μg/mL, respectively. Crude extracts from the twig and stem bark of C. patens displayed inhibition at MIC values of 125 μg/mL and 100 μg/mL, respectively. Majority of active extracts showed no cell cytotoxicity, except the extract from C. patens with IC50 ranging from 41.40 μg/mL to 93.78 μg/mL. The chemical investigation of the promising extracts revealed the presence of phenols, alkaloids, glycosides, triterpenes, and acetogenins. Conclusion: The results achieved from this preliminary antimycobacterial drug discovery study supported the traditional claims of C. patens, A. reticulata, and G. suaveolens in the treatment of mycobacterial infections. Meanwhile, further fractionation is required to characterize the active ingredients