Effect of lignocellulose/montmorillonite immobilized Bacillus sp. on monosodium glutamate wastewater.

A group of Bacillus sp. was extracted from monosodium glutamate wastewater. Lignocellulose/montmorillonite composite was selected as the carrier. Lignocellulose/montmorillonite composite immobilized Bacillus sp./calcium alginate microspheres were prepared by immobilized microorganism techniques. The microspheres were used to treat monosodium glutamate wastewater with significantly reduced ammonia nitrogen (NH3-N) and chemical oxygen demand (COD) concentrations. The optimum preparation conditions of microspheres in the treatment of NH3-N and COD of monosodium glutamate wastewater were studied. The concentration of sodium alginate was 2.0 wt%, lignocellulose/montmorillonite was 0.06 wt%, Bacillus sp. was 1.0 wt%, CaCl2 solution was 2.0 wt%, coagulation time was 12 h, and the removal capacities of NH3-N and COD were 44832 and 78345 mg/L, respectively. The surface structure, element content, functional group change, and crystal structure of the microspheres were characterized by SEM, EDS, and other methods. The results showed that the -COOH in lignocellulose/montmorillonite and the -OH in the Bacillus sp. form intermolecular hydrogen bonds. The Si-O and Al-O bonds in lignocellulose/montmorillonite reacted with sodium ions in sodium alginate. New crystal structures appear inside the material after crosslinking, and the microspheres was formed. Thus, the study has shown that the microspheres were successfully prepared and contributes to the treatment of NH3-N and COD in monosodium glutamate wastewater. This work can provide an interesting strategy for the removal of COD and NH3-N in industrial wastewater by reasonably combining bio-physicochemical processes.

Adjusting irradiance to enhance growth and lipid production of Chlorella vulgaris cultivated with monosodium glutamate wastewater.

Light is one of the most important factors affecting microalgae growth and biochemical composition. The influence of illumination on Chlorella vulgaris cultivated with diluted monosodium glutamate wastewater (MSGW) was investigated. Six progressive illumination intensities (0, 30, 90, 150, 200 and 300µmol·m(-2)s(-1)), were used for C. vulgaris cultivation at 25°C. Under 150µmol·m(-2)s(-1), the corresponding specific light intensity of 750×10(-6)µmol·m(-2)s(-1) per cell, algae obtained the maximum biomass concentration (1.46g·L(-1)) on the 7th day, which was 3.5 times of that under 0µmol·m(-2)s(-1), and the greatest average specific growth rate (0.79 d(-1)) in the first 7days. The results showed the importance role of light in mixotrophic growth of C. vulgaris. High light intensities of 200 and 300µmol·m(-2)s(-1) would inhibit microalgae growth to a certain degree. The algal lipid content was the greatest (30.5%) at 150µmol·m(-2)s(-1) light intensity, which was 2.42 times as high as that cultured in dark. The protein content of C. vulgaris decreased at high light intensities of 200 and 300µmol·m(-2)s(-1). The effect of irradiance on carbohydrate content was inversely correlated with that on protein. The available light at an appropriate intensity, not higher than 200µmol·m(-2)s(-1), was feasible for economical cultivation of C. vulgaris in MSGW.

Impacts of industrial waste resources on maize (Zea mays L.) growth, yield, nutrients uptake and soil properties.

Discharging untreated highly acidic (pH<4.0), organic and nutrients rich monosodium glutamate wastewater (MW), and highly alkaline (pH>10.0) paper-mill wastewater (PW) causes environmental pollution. When acidity of MW neutralized (pH 6.5±0.1) with PW and lime (treatments represented as MW+PW and MW+Lime), then MW may be utilized as a potential source of nutrients and organic carbon for sustainable food production. Objectives of this study were to compare the effects of PW and lime neutralized MW and chemical fertilizers on maize (Zea mays L. cv. Snow Jean) plant growth, yield, nutrients uptake, soil organic matter and humic substances. The field experiment was carried out on maize using MW at 6000 L ha(-1). Impacts of the MW application on maize crop and soil properties were evaluated at different stages. At harvest, plant height, and plant N and K uptake were higher in MW treatment. Leaf area index at 60 days after sowing, plant dry matter accumulation at harvest, and kernels ear(-1) and 100-kernel weight were higher in MW+Lime treatment. Kernel N, P, K, Mn, Fe and Zn, and plant Zn uptake were highest in MW+Lime. Plant Fe uptake, and soil organic matter and humic substances were highest in MW+PW. The MW+PW and MW+Lime treatments exhibited comparable results with chemically fertilized treatment. The MW acidity neutralized with lime showed positive impacts on growth, yield and nutrients uptake; nevertheless, when MW pH neutralized with PW has an additional benefit on increase in soil organic matter and humic substances.

Effects of a nutrient additive on the density of functional bacteria and the microbial community structure of bioorganic fertilizer.

In this study, a secondary composting experiment was conducted to investigate the effects of concentrated monosodium glutamate wastewater (CMGW) as a nutrient additive on enhancing the density of functional bacteria in bioorganic fertilizer (BOF). The results showed that, as the CMGW was added, the composting mixture temperature rose more quickly and strongly, and the functional bacteria Bacillus subtilis F2 percentage in spores increased significantly. Furthermore, both the highest species richness value (Rs) of a given sample and similarity coefficient value (Cs) between a sample and strain F2 based on DGGE analysis were also observed in the treatment with CMGW. A similar effect of CMGW on the microbial community structure was verified by means of illumine-MiSeq sequencing. It may thus be concluded that CMGW is a recommendable nutrient additive for F2 predominating in the secondary composting process.

Mixotrophic growth and biochemical analysis of Chlorella vulgaris cultivated with diluted monosodium glutamate wastewater.

Monosodium glutamate wastewater (MSGW) is a potential medium for microbial cultivation because of containing abundant organic nutrient. This paper seeks to evaluate the feasibility of growing Chlorella vulgaris with MSGW and assess the influence of MSGW concentration on the biomass productivity and biochemical compositions. The MSGW diluted in different concentrations was prepared for microalga cultivation. C. vulgaris growth was greatly promoted with MSGW compared with the inorganic BG11 medium. C. vulgaris obtained the maximum biomass concentration (1.02 g/L) and biomass productivity (61.47 mg/Ld) with 100-time diluted MSGW. The harvested biomass was rich in protein (36.01-50.64%) and low in lipid (13.47-25.4%) and carbohydrate (8.94-20.1%). The protein nutritional quality and unsaturated fatty acids content of algal increased significantly with diluted MSGW. These results indicated that the MSGW is a feasible alternative for mass cultivation of C. vulgaris.