Screening of microorganisms for hydrolyases with commercial potential

Advancement in green chemistry has increased the use of microbial hydrolyases in various industries and chemical processes because of high catalytic efficiency, specificity, cost-effectiveness and eco-friendly nature. Bioconversion of tannins such as tannic acid is achieved by tannin acyl hydrolase, also known as tannase. It converts tannic acid into glucose and gallic acid by catalyzing the hydrolysis of ester and depside linkages in tannic acid. Tyrosinase is monophenol and O-diphenol oxidase a copper containing enzyme catalyzes the oxidation of tyrosine and generates different types of pigment such as melanin. Xylanases hydrolyze xylan into its constituent sugar with the help of several debranching enzymes. Microbial strains isolated from various sources were screened for these hydrolyases: Bhavnagar marine salterns (Bacillus megaterium BVUC_01 and Bacillus licheniformis BVUCh_02); Okhamadhi marine salterns Aspergillus versicolor; Spoiled/infected pomegranate (Xenoacremonium falcatum, two strains PGF1 and PGF4, Bacillus velezensisPGF2 and Candida freyschussiiPGF3. The other laboratory maintained bacterial cultures namely, Bacillus subtilis, Pseudomonas aeruginosa, Staphylococcus aureus, Salmonella typhi were also used in this study. Asp. versicolor and Xen. falcatum (PGF1) produced all the three enzymes (tannase, tyrosinase and xylanase). B. licheniformis, B. megaterium, B. subtilis, B. velezensis produced tyrosinase and xylanase. Xen. falcatum (PGF4) and PGF2 produced tannase and xylanase. PGF3 produced tannase and tyrosinase. While, Bacillus megaterium and Salmonella typhi showed only tyrosinase activity. Candida freyschussii showed tannase activity. Staphylococcus aureus did not produce any of these enzymes.

Comparative Characterization and Identification of Poly-3-Hydroxybutyrate Producing Bacteria with Subsequent Optimization of Polymer Yield

In this work, the strains Bacillus megaterium BM 1, Azotobacter chrocococcumAz 3, Bacillus araybhattay RA 5 were used as an effective producer of poly-3-hydroxybutyrate P(3HB). The purpose of the study was to isolate and obtain an effective producer of P(3HB) isolated from regional chestnut soils of northern Kazakhstan. This study demonstrates the possibility of combining the protective system of cells to physical stress as a way to optimize the synthesis of PHA by strains. Molecular identification of strains and amplification of the phbC gene, transmission electron microscope (TEM), extracted and dried PHB were subjected to Fourier infrared transmission spectroscopy (FTIR). The melting point of the isolated P(3HB) was determined. The optimal concentration of bean broth for the synthesis of P(3HB) for the modified type of Bacillus megaterium RAZ 3 was 20 g/L, at which the dry weight of cells was 25.7 g/L−1 and P(3HB) yield of 13.83 g/L−1, while the percentage yield of P(3HB) was 53.75%. The FTIR spectra of the extracted polymer showed noticeable peaks at long wavelengths. Based on a proof of concept, this study demonstrates encouraging results.

Hiệu quả của chế phẩm vi sinh chịu mặn NPISi lên sinh trưởng, năng suất lúa và đặc tính đất nhiễm mặn mô hình tôm-lúa tại huyện Phước Long, tỉnh Bạc Liêu

Mục tiêu của nghiên cứu là đánh giá hiệu quả của chế phẩm vi sinh chịu mặn NPISi chứa các dòng vi khuẩn Bacillus aquimaris KG6-3, Burkholderia sp. BL1-10, Bacillus megaterium ST2-9 và Citrobacter freundii RTTV_12 lên sinh trưởng, năng suất giống lúa Một Bụi Đỏ và đặc tính đất nhiễm mặn trong mô hình canh tác tôm-lúa ở huyện Phước Long, tỉnh Bạc Liêu. Thí nghiệm được bố trí thể thức khối hoàn toàn ngẫu nhiên gồm 4 nghiệm thức và 4 lần lặp lại. Kết quả nghiên cứu cho thấy các nghiệm thức có sử dụng chế phẩm vi sinh chịu mặn NPISi với liều lượng 75 kg/ha cho hàm lượng Si tổng số, N tổng số, P tổng số, K tổng số trong thân và năng suất lúa cao hơn và khác biệt ý nghĩa thống kê (p<0,05) so với nghiệm thức đối chứng chỉ sử dụng phân NPK theo kinh nghiệm của nông dân. Bên cạnh đó, việc sử dụng chế phẩm vi sinh chịu mặn NPISi còn giúp cải thiện một số đặc tính hóa học và sinh học đất như hàm lượng đạm hữu dụng, P dễ tiêu, mật số vi khuẩn, mật số vi khuẩn cố định đạm, vi khuẩn hòa tan lân và vi khuẩn hòa tan Si trong đất ở thời điểm kết thúc thí nghiệm.

Self-healing mortar using different types, content, and concentrations of bacteria to repair cracks.

The creation of cracks, which are the most common cause of structural failure, has a significant impact on the structure's strength and durability. As a result, effective repair and maintenance are vital and unavoidable for treating any of these issues. Self-healing mortar holds promising benefits for reducing the cost of repair as cracks are autonomously repaired without any human intervention. This study investigated the effect of bacteria type, bacteria content, bacteria concentration, and nutrient type on the properties of the self-healing mortar. Three types of bacteria, Bacillus sphaericus, Bacillus Megaterium, and Bacillus subtilis encapsulated in calcium alginate beads, were introduced into the mortar. Two concentrations of bacteria, 2× 108 and 2× 109 Colony Forming Units per milliliter, and different percentages of bacteria of cement weight were selected for the study. In addition, calcium lactate and calcium acetate were used at 0.5% of cement weight as nutrition for bacteria. Tests were performed for compressive strength, bending strength, SEM, EDX, and TGA/DTG. The results show a significant development in the mechanical behaviour of mortar, especially with Bacillus Megaterium using a 2.5% bacterial proportion with a concentration 2× 109 CFU/ml. This can be related to the filling of voids and cracks in microbial mortar by calcite, which was confirmed by SEM and EDX.

Mitigation of CaCO3 Influences on Ipomoea batatas Plants Using Bacillus megaterium BSM 2894 var.

Under Egyptian soil conditions, when phosphorus fertilizers were applied to the soil, it gets fixed and converts to unavailable form, leading to low solubility for the plant. This study were fulfilled on sweet potato (cv. Beauregard) under undesirable soil properties (CaCO3 10.8 vs 11.3%) using Bacillus megaterium DSM 2894 strain under different five mono calcium phosphate (CSP) levels [(69(CSP20); 138(CSP40); 207 (CSP60); 276 (CSP80) and 345 ((CSP100) kg ha-1 of calcium superphosphate (CSP)] to arise the potential efficiency of some nutrients uptake and decease the applied total amount of CSP in 2019 and 2020 seasons. The results mentioned that highest values were obtained by inoculated plants with DSM2894 strain under 20, 60 and 100% of CSP for all studied nutrients content in both seasons, except Mn content in the 2019. Also, inoculated plants with DSM2894 under previous treatments for all tuberous root nutrients content, except Fe and Zn contents in both seasons, in addition protein and anti-radical power and total yield. Statistically, leaf nutrients uptake and tuberous root content were highly significant affected by DSM and CSP combination. Appling of phosphorus fertilizer with DSM2894 mixture was gave the best values as compared with phosphorus fertilizer or DSM2894, individually.

Aquaculture Water Quality Improvement by Mixed Bacillus and Its Effects on Microbial Community Structure

Nutrients nitrogen and phosphorus pollution in aquaculture is one of the greatest challenges threatening the survival of aquatic organisms, which requires efficient and sustainable remediation approach. Microbial remediation, especially the application of probiotics, has recently gained popularity in improving the water quality and maintaining the health condition of aquatic animals. In the present study, two groups of mixed Bacillus (Bacillus megaterium and Bacillus subtilis (A0+BS) and Bacillus megaterium and Bacillus coagulans (A0+BC)) were applied to aquaculture system of Crucian carp to improve the treatment of nitrogenous and phosphorus compounds. The effects of mixed Bacillus on water quality, and the structure and function of microbial communities in aquaculture water were investigated. Our results showed that the improvement effect of mixed Bacillus A0+BS on water quality was better than that of A0+BC, and the NH4+-N, NO2--N, NO3--N and total phosphorus (TP) concentrations were reduced by 46.3%, 76.3%, 35.6%, and 80.3%, respectively. In addition, both groups of mixed Bacillus increased the diversity of bacterial community and decreased the diversity of fungal community. Microbial community analysis showed that mixed Bacillus A0+BS increased the relative abundance of bacteria related with nitrogen and phosphorus removal, e.g., Proteobacteria, Actinobacteria, Comamonas, and Stenotrophomonas, but decreased the relative abundance of pathogenic bacteria (Acinetobacter and Pseudomonas) and fungi (Epicoccum and Fusarium). The redundancy analysis showed that NH4+-N, NO2--N, and TP were primary environmental factors affecting the microbial community in aquaculture water. PICRUST analysis indicated that all functional pathways in the treatment groups were up-regulated, and all pathways in A0+BS group were richer than those in other groups. These results indicated that mixed Bacillus A0+BS addition produced good results in reducing nitrogenous and phosphorus compounds and shaped a favorable microbial community structure to further improve water quality.

Lead-Tolerant Bacillus Strains Promote Growth and Antioxidant Activities of Spinach (Spinacia oleracea) Treated with Sewage Water

Irrigation with sewage-contaminated water poses a serious threat to food security, particularly in developing countries. Heavy metal tolerant bacteria are sustainable alternatives for the removal of wastewater contaminants. In the present study, four lead (Pb)-tolerant strains viz. Bacillus megaterium (N8), Bacillus safensis (N11), Bacillus sp. (N18), and Bacillus megaterium (N29) were inoculated in spinach and grown in sewage water treated earthen pots separately and in combination with canal water. Results showed that Pb-tolerant strains significantly improved plant growth and antioxidant activities in spinach and reduces metal concentration in roots and leaves of spinach plants irrigated with treated wastewater. Strain Bacillus sp. (N18) followed by B. safensis (N11) caused the maximum increase in shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, and leaf area compared to the uninoculated control of sewage water treated plants. These strains also improved antioxidant enzymatic activity including catalase, guaiacol peroxidase dismutase, superoxide dismutase, and peroxidases activities compared to the uninoculated control under sewage water conditions. Strain Bacillus sp. (N18) followed by B. safensis (N11) showed the highest reduction in nickel, cadmium, chromium, and Pb contents in roots and leaves of spinach compared to the uninoculated control plants treated with the sewage water. Such potential Pb-tolerant Bacillus strains could be recommended for the growth promotion of spinach after extensive evaluation under field conditions contaminated with wastewater.