Mechanical and self-healing properties of cement paste containing incinerated sugarcane filter cake and Lysinibacillus sp. WH bacteria.

Cement is the most widely used construction material due to its strength and affordability, but its production is energy intensive. Thus, the need to replace cement with widely available waste material such as incinerated black filter cake (IBFC) in order to reduce energy consumption and the associated CO2 emissions. However, because IBFC is a newly discovered cement replacement material, several parameters affecting the mechanical properties of IBFC-cement composite have not been thoroughly investigated yet. Thus, this work aims to investigate the impact of IBFC as a cement replacement and the addition of the calcifying bacterium Lysinibacillus sp. WH on the mechanical and self-healing properties of IBFC cement pastes. The properties of the IBFC-cement pastes were assessed by determining compressive strength, permeable void, water absorption, cement hydration product, and self-healing property. Increases in IBFC replacement reduced the durability of the cement pastes. The addition of the strain WH to IBFC cement pastes, resulting in biocement, increased the strength of the IBFC-cement composite. A 20% IBFC cement-replacement was determined to be the ideal ratio for producing biocement in this study, with a lower void percentage and water absorption value. Adding strain WH decreases pore sizes, densifies the matrix in ≤ 20% IBFC biocement, and enhances the formation of calcium silicate hydrate (C-S-H) and AFm ettringite phases. Biogenic CaCO3 and C-S-H significantly increase IBFC composite strength, especially at ≤ 20% IBFC replacement. Moreover, IBFC-cement composites with strain WH exhibit self-healing properties, with bacteria precipitating CaCO3 crystals to bridge cracks within two weeks. Overall, this work provides an approach to produce a "green/sustainable" cement using biologically enabled self-healing characteristics.

Investigating the effects of superplasticizer and recycled plastics on the compressive strength of cementitious composites using neural networks.

The potential application of neural network (NN) models to estimate the compressive strength (CS) of cementitious composites under a variety of experimental settings and cement mixes was investigated. The data were extensively collected from previous literature, and the bootstrap resampling tests were applied to estimate the statistics of the parameter correlations. We find that the NN model that involves the coarse and fine natural aggregates (CA and FA), superplasticizer (SP) and recycled plastics (RP) as the features can accurately predict the CS (R2 ∼ 0.9), without the need to specify the type of SP and the structure of RP in advance. The developed NN model holds promise for revealing the global dependency of CS on these parameters. It suggested that increasing 100 kg/m3 of CA could increase CS by ∼4 MPa, but the usage of CA more than 700 kg/m3 could negatively affect CS. How the CS varying with FA is apparently nonlinear. Within the optimum limit, adding 1 kg/m3 of SP could enhance the CS by ∼2 MPa. Contrarily, additional 1 kg/m3 of RP results in a decrease of ∼0.2 MPa of CS. The mixture-type independent models developed here would broaden our understanding of the global influential-sensitivity among these variables and help save cost and time in the industrial applications.

The Potential of Endophytic Fungi for Enhancing the Growth and Accumulation of Phenolic Compounds and Anthocyanin in Maled Phai Rice (Oryza sativa L.).

Rice (Oryza sativa L.) is one of the most popular cereal crops, being consumed by almost half of the world's population. Among several cultivars widely distributed in Thailand, Maled Phai is a Thai pigmented-upland rice with exceptionally high nutritional value and high demand in the local Thai market. This study aimed to investigate the feasibility of producing plant growth-promoting properties (PGP) and enhancing the accumulation of phytochemicals in Maled Phai rice seeds of endophytic fungi isolated from upland black rice. Among a total of 56 isolates, the 4 most effective PGP isolates were identified as Trichoderma zelobreve PBMP16, Talaromyces pinophilus PBMP28, Aspergillus flavus KKMP34, and Trichoderma sp. PBMP4 based on their morphological characteristics and multigene (ITS, rpb2, tef-1, CaM, and BenA) phylogenetic analyses. These four endophytic fungi could promote plant growth parameters under greenhouse conditions. Outstandingly, upland rice inoculated with Tr. zelobreve PBMP16 had a significant increase in total seed weight, root length, phenolic compounds, anthocyanin, antioxidants, and N uptake, which were higher than those of the noninoculated control, and even better than the chemical fertilizer. Overall, this report shows that endophytic fungi efficiently promoted growth and increased the phenolic compounds, anthocyanin, and antioxidants of Maled Phai rice.

Promoting growth and production of sunchoke (Helianthus tuberosus) by co-inoculation with phosphate solubilizing bacteria and arbuscular mycorrhizal fungi under drought.

Due to different functions of phosphate solubilizing bacteria (PSB) and arbuscular mycorrhizal fungi (AMF), their potential synergistic effects on enhancing plant growth and yield are worth investigating, especially under adverse conditions. This work focused on the isolation of PSB and characterization for their plant growth promoting properties under drought. The most efficient P solubilizing bacterium was isolated and identified as Burkholderia vietnamiensis strain KKUT8-1. Then, a factorial experiment on the performance of sunchoke (Helianthus tuberosus) was set up with four factors, viz., PSB (presence or absence of KKUT8-1), AMF (presence or absence of Rhizophagus aggregatus), rock phosphate (RP; added or not) and moisture (well-watered (WW) or drought (DS) conditions). Sunchoke performance was enhanced by the presence of AMF, whereas addition of PSB had a positive effect on SPAD values and inulin concentration. Drought reduced plant performance, while addition of RP reduced photosynthetic rate. There was little evidence for synergistic effects between PSB and AMF, except for SPAD values and inulin concentration. Plants that were co-inoculated with AMF and PSB had highest SPAD value, shoot diameter, leaf area, leaf number, chlorophyll concentration, plant biomass, tuber production, root growth and total soluble sugar concentration. Co-inoculated plants also had increased plant water status, reduced electrolyte leakage, and reduced malondialdehyde and proline concentration. Strain KKUT8-1 is the first strain of B. vietnamiensis capable of promoting growth and yield of sunchoke. Enhanced production of sunchoke by a combination of AMF and PSB was much better than the application of RP. Our finding offers an opportunity to develop combinations of biological inoculants for increasing the growth and production of sunchoke under drought in the future.

Enhancement of growth and Cannabinoids content of hemp (Cannabis sativa) using arbuscular mycorrhizal fungi.

This study aimed to investigate the efficiency of arbuscular mycorrhizal fungi (AMF) to promote growth and cannabinoid yield of Cannabis sativa KKU05. A completely randomized design (CRD) was conducted with six replications for 60 days. Two different species of AMF, Rhizophagus prolifer PC2-2 and R. aggregatus BM-3 g3 were selected as inocula and compared with two non-mycorrhizal controls, one without synthetic fertilizer and one with synthetic NPK fertilizer. The unfertilized non-mycorrhizal plants had the lowest performance, whereas plants inoculated with R. aggregatus BM-3 g3 performed best, both in terms of plant biomass and concentrations of CBD and THC. There were no significant differences in plant biomass and cannabinoid concentrations between non-mycorrhizal plants that received synthetic fertilizer and mycorrhizal plants with inoculum of R. prolifer PC2-2. Our data demonstrate the great potential for cannabis cultivation without risking deterioration of soil structure, such as soil hardening and increased acidity, which might be induced by long-term use of synthetic fertilizer.

Bio-strengthening of cementitious composites from incinerated sugarcane filter cake by a calcifying bacterium Lysinibacillus sp. WH.

This study investigated Microbially Induced Calcite Precipitation (MICP) technology to improve the mechanical properties of cementitious composites containing incinerated sugarcane filter cake (IFC) using a calcifying bacterium Lysinibacillus sp. WH. Both IFC obtained after the first and second clarification processes, referred to as white (IWFC) and black (IBFC), were experimented. This is the first work to investigate the use of IBFC as a cement replacement. According to the X-ray fluorescence (XRF) results, the main element of IWFC and IBFC was CaO (91.52%) and SiO2 (58.80%), respectively. This is also the first work to investigate the use of IBFC as a cement replacement. We found that the addition of strain WH could further enhance the strength of both cementitious composites up to ~ 31%, while reduced water absorption and void. Microstructures of the composites were visualized using a scanning electron microscope (SEM). The cement hydration products were determined using X-ray diffraction (XRD) followed by Rietveld analysis. The results indicated that biogenic CaCO3 was the main composition in enhancing strength of the IBFC composite, whereas induce tricalcium silicate (C3S) formation promoting the strength of IWFC composite. This work provided strong evidence that the mechanical properties of the cementitious composites could be significantly improved through the application of MICP. In fact, the strength of IFC-based cementitious composites after boosting by strain WH is only 10% smaller than that of the conventional Portland cement. While using IFC as a cement substitute is a greener way to produce environmentally friendly materials, it also provides a solution to long-term agro-industrial waste pollution problems.

Kinetic model of a newly-isolated Lysinibacillus sp. strain YL and elastic properties of its biogenic CaCO3 towards biocement application.

BACKGROUND: Biocement, calcifying bacteria-incorporated cement, offers an environmentally-friendly way to increase the cement lifespan. This work aimed to investigate the potential use of Lysinibacillus sp. strain YL towards biocement application in both theoretical and experimental ways. METHODS AND RESULTS: Strain YL was grown using calcium acetate (Ca(C2 H3 O2 )2 ), calcium chloride (CaCl2 ) and calcium nitrate (Ca(NO3 )2 ). Maximum bacterial growth of ~0.09 hr-1 and the highest amount of CaCO3 precipitation of ~8.0 g/L were obtained when using Ca(C2 H3 O2 )2 . The SEM and XRD results confirmed that biogenic CaCO3 were calcites. The bulk, Young's and shear moduli of biogenic CaCO3 calculated via the VRH approximation were ~1.5-2.3 times larger than those of ordinary Portland cement. The Poisson's ratio was 0.382 and negative in some directions, suggesting its ductility and auxetic behaviors. The new model was developed to explain the growth kinetic of strain YL in the presence of Ca(C2 H3 O2 )2 , whose concentration was optimized for biocement experiments. Strain YL could increase the compressive strength of cement up to ~50% higher than that of the uninoculated cement. CONCLUSION: Strain YL is a promising candidate for biocement applications. This work represents the trials of experiments and models allowing quantitatively comparison with large-scale production in the future.

Co-Inoculation of an Endophytic and Arbuscular Mycorrhizal Fungus Improve Growth and Yield of Helianthus tuberosus L. under Field Condition.

Endophytic fungi (EPF) and arbuscular mycorrhizal fungi (AMF) symbioses can promote the growth and productivity of several types of plants. This work aimed to investigate the effect of co-inoculation of an EPF Exserohilum rostratum NMS1.5 and an AMF Glomus etunicatum UDCN52867 g.5 on the growth and yields of sunchoke (Helianthus tuberosus L.) compared to the effects of full-dose and half-dose chemical fertilizer (15-15-15) under field conditions. Several plant growth parameters of the co-inoculated plants were significantly higher than the other treatments. Remarkably, such an effect was relatively equal to that of the full-dose chemical fertilizers. Moreover, the co-inoculation of EPF and AMF significantly improved the tuber yield production, even better than the use of a chemical fertilizer. This is the first report to show that plant growth promoting effects of the co-inoculation of EPF and AMF were exceptionally greater than those of the chemical fertilizer. Therefore, our EPF and AMF could potentially be used as a biofertilizer for promoting the growth and yield of sunchoke in the fields.

Combination of arbuscular mycorrhizal fungi and phosphate solubilizing bacteria on growth and production of Helianthus tuberosus under field condition.

In this work, the effects of co-inoculation between an arbuscular mycorrhizal fungus (AMF) and a phosphate solubilizing bacteria (PSB) to promote the growth and production of sunchoke under field condition were investigated during 2016 and 2017. Four treatments were set up as follows: plants without inoculation, with AMF inoculation, with PSB inoculation and with co-inoculation of PSB and AMF. The results showed the presence of PSB and AMF colonization at the harvest stage in both years. This suggested the survival of PSB and successful AMF colonization throughout the experiments. According to correlation analysis, PSB positively affected AMF spore density and colonization rate. Also, both AMF and PSB positively correlated with growth and production of sunchoke. Co-inoculation could enhance various plant parameters. However, better results in 2016 were found in co-inoculation treatment, while AMF inoculation performed the best in 2017. All of these results suggested that our AMF and PSB could effectively promote growth and production of sunchoke under field conditions. Such effects were varied due to different environmental conditions each year. Note that this is the first study showing successful co-inoculation of AMF and PSB for promoting growth and yield of sunchoke in the real cultivation fields.

Purification, characterization and partial amino acid sequences of thermo-alkali-stable and mercury ion-tolerant xylanase from Thermomyces dupontii KKU-CLD-E2-3.

We investigated the properties of the low molecular weight thermo-alkali-stable and mercury ion-tolerant xylanase production from Thermomyces dupontii KKU-CLD-E2-3. The xylanase was purified to homogeneity by ammonium sulfate, Sephadex G-100 and DEAE-cellulose column chromatography which resulted 27.92-fold purification specific activity of 56.19 U/mg protein and a recovery yield of 2.01%. The purified xylanase showed a molecular weight of 25 kDa by SDS-PAGE and the partial peptide sequence showed maximum sequence homology to the endo-1,4-ß-xylanase. The optimum temperature and pH for its activity were 80 °C and pH 9.0, respectively. Furthermore, the purified xylanase can maintain more than 75% of the original activity in pH range of 7.0-10.0 after incubation at 4 °C for 24 h, and can still maintain more than 70% of original activity after incubating at 70 °C for 90 min. Our purified xylanase was activated by Cu2+ and Hg2+ up to 277% and 235% of initial activity, respectively but inhibited by Co2+, Ag+ and SDS at a concentration of 5 mM. The Km and Vmax values of beechwood xylan were 3.38 mg/mL and 625 µmol/min/mg, respectively. Furthermore, our xylanase had activity specifically to xylan-containing substrates and hydrolyzed beechwood xylan, and the end products mainly were xylotetraose and xylobiose. The results suggested that our purified xylanase has potential to use for pulp bleaching in the pulp and paper industry.

Investigating mechanical properties and biocement application of CaCO3 precipitated by a newly-isolated Lysinibacillus sp. WH using artificial neural networks.

A newly-isolated Lysinibacillus sp. strain WH could precipitate CaCO3 using calcium acetate (Ca(C2H3O2)2), calcium chloride (CaCl2) and calcium nitrate (Ca(NO3)2) via non-ureolytic processes. We developed an algorithm to determine CaCO3 crystal structures by fitting the simulated XRD spectra to the experimental data using the artificial neural networks (ANNs). The biogenic CaCO3 crystals when using CaCl2 and Ca(NO3)2 are trigonal calcites with space group R3c, while those when using Ca(C2H3O2)2 are hexagonal vaterites with space group P6522. Their elastic properties are derived from the Voigt-Reuss-Hill (VRH) approximation. The bulk, Young's, and shear moduli of biogenic calcite are 77.812, 88.197, and 33.645 GPa, respectively, while those of vaterite are 67.082, 68.644, 25.818 GPa, respectively. Their Poisson's ratios are ~ 0.3-0.33, suggesting the ductility behavior of our crystals. These elastic values are comparable to those found in limestone cement, but are significantly larger than those of Portland cement. Based on the biocement experiment, the maximum increase in the compressive strength of Portland cement (27.4%) was found when Ca(NO3)2 was used. An increased strength of 26.1% was also found when Ca(C2H3O2)2 was used, implying the transformation of less-durable vaterite to higher-durable calcite. CaCO3 produced by strain WH has a potential to strengthen Portland cement-based materials.

Improved Biosurfactant Production by Enterobacter cloacae B14, Stability Studies, and its Antimicrobial Activity.

This work aimed to optimize carbon and nitrogen sources for the growth of Enterobacter cloacae B14 and its biosurfactant (BS) production via One-Variable-At-a-Time (OVAT) method. The BS stability under a range of pH and temperatures was assessed. Antimicrobial activity against Gram-positive and Gram-negative pathogens was determined by the agar well diffusion method. The results showed that the optimum carbon and nitrogen sources for BS production were maltose and yeast extract, respectively, with a maximum BS yield of (39.8 ± 5.2) mg BS/g biomass. The highest emulsification activity (E24) was 79%, which is significantly higher than in the previous studies. We found that B14 BS can withstand a wide range of pH values from 2 to10. It could also function under a range of temperatures from 30-37°C. Thin Layer Chromatography (TLC) and Fourier Transform Infrared Spectrometry (FTIR) analysis confirmed that B14 BS is a glycolipid-like compound, which is rarely found in Enterobacter spp. Cell-free broth showed inhibition against various pathogens, preferable to Gram-positive ones. It had better antimicrobial activity against Bacillus subtilis than a commonly-used antibiotic, tetracycline. Furthermore, B14 broth could inhibit the growth of a tetracycline-resistant Serratia marcescens. Our results showed promising B14 BS applications not only for bioremediation but also for the production of antimicrobial products.