Rana Pratap Singh

Utilizing monoalgal species for wastewater treatment is facing tremendous challenges owing to changing wastewater complexity in terms of physico-chemical characteristic, nutrient and metal concentration. The environmental conditions are also fluctuating therefore, the formation of robust system is of utmost importance for concomitant sustainable wastewater treatment and bioenergy production. In the present study, the tolerance and adaptability potential of algal consortia-1 (Chlorococcum humicola and Tetradesmus sp.) and consortia-2 (Chlorococcum humicola, Scenedesmus vacuolatus and Tetradesmus sp.) treated with municipal wastewater were examined under natural environmental conditions. The results exhibited that consortia-2 was more competent in recovering nitrate-nitrogen (82.92%), phosphorus (70.47%), and heavy metals (31–73.70%) from municipal wastewater (100%) than consortia-1. The results further depicted that total chlorophyll, carbohydrate, and protein content decreased significantly in wastewater-treated consortia-1 as compared to consortia-2. However, lipid content was increased by 4.01 and 1.17 folds in algal consortia-1 and consortia-2 compared to their respective controls. Moreover, absorption peak at 1740.6 cm⁻¹ reflected higher biofuel-producing potential of consortia-1 as compared to consortia-2 as confirmed through FTIR spectroscopy. The results also revealed that consortia-2 showed the highest photosynthetic performance which was evident from the increment in the active photosystem-II reaction center (1.724 ± 0.068), quantum efficiency (0.633 ± 0.038), and performance index (3.752 ± 0.356). Further, a significant increase in photosynthetic parameters was observed in selected consortia at lag phase, while a noteworthy decline was observed at exponential and stationary phases in consortia-1 than consortia-2. The results also showed the maximum enhancement in ascorbic acid (2.43 folds), proline (3.34 folds), and cysteine (1.29 folds) in consortia-2, while SOD (1.75 folds), catalase (2.64 folds), and GR (1.19 folds) activity in consortia-1. Therefore, it can be concluded that due to remarkable flexibility and photosynthetic performance, consortia-2 could serve as a potential candidate for sustainable nutrient resource recovery and wastewater treatment, while consortia-1 for bio-fuel production in a natural environment. Thus, formation of algal consortia as the robust biosystem tolerates diverse environmental fluctuations together with wastewater complexity and ultimately can serve appropriate approach for environmental-friendly wastewater treatment and bioenergy production. Graphical Abstract

The current study was undertaken to determine the ability of different carrier materials for sustaining the viability of microbial consortium during storage. Different bioformulations consisting of carrier material and microbial consortium were prepared and examined for viability and stability for one year stored at 4 °C and ambient temperature. Total 8 bio-formulations were prepared consisting five economically viable carriers (gluten, talc, charcoal, bentonite, broth medium) and a microbial consortium. In present study, maximum enhanced shelf-life of consortium based on colony forming unit count were recorded for talc + gluten based (B4) bioformulation (9.03 log₁₀ cfu/g) over other bio-formulations stored for 360 days. Furthermore, the pot experiments was conducted to evaluate the efficacy of B4 formulation on growth of spinach in comparison with recommended dose of chemical fertilizer, uninoculated and no amendment control. The results depicted that B4 formulation increased biomass (176–666%), leaf area (33–123%), chlorophyll content (131–789%) and protein content (68.4–94.4%) of spinach over controls. Further B4 application significantly increased the nutrients like available nitrogen (131–475%), phosphorus (75–178%) and potassium (31–191%) of pot soil along with noteworthy improvement in root colonization as evident from scanning electron microscope analysis in comparison to controls at 60 days after sowing. Therefore, exploiting B4 formulation can serve as the environmentally sound approach to enhance the productivity, biomass and nutritional value of spinach. Thus, Plant growth promoting microbes-based formulation can be the novel paradigm to improve the soil health and eventually the crop productivity in economical and sustainable manner.

The present study investigates bioaccumulation factor (B_fc), Edaphic pollution indices and associated health risk assessment of trace metals (TMs) i.e., Cu, Fe, Zn, Mn and Co in the crops, agricultural soil (AgS), and irrigation water (IgW) collected from various peri-urban area of metropolitan city of India, Lucknow. Though the level of these TMs was within the permissible limits (PL) (FAO/WHO, 2011) in AgS and IgW however it was higher than PL in tomato, spinach and wheat cultivated in the fields. The bioaccumulation factor of Cu, Fe and Mn in edible parts of tomato, spinach and wheat was 8 to 25 times higher through the AgS and 10 to 300 times higher through the IgW in the tomato, spinach and wheat samples. The enrichment factor (E^fc), contamination factor (C^fc), contamination degree (C_dg) and modified contamination degree (mC_dg) values of Co, Cu, Mn, Fe and Zn ranged from low to high levels of contamination, whereas the geo-accumulation index reflected low contamination in agricultural soil. on the other hand, the metal pollution load index (M_pi) was found strongly contaminated in most of the study areas. Due to the consumption of these contaminated vegetables and cereal (VCs) by human consumers, the hazard quotient (HQ), total hazard quotient (THQ) and hazard index (HI) were found to be more than the requisite value of 1, which indicates a far-long health risk in this crowded city and its surrounding regions.

The incidence of biotic perturbation in plants has been amplified due to increased resistance and the resurgence of pathogens. To mitigate stress and promote food production, agrochemicals are being used boundlessly and they have augmented the problem of disease re-occurrence and agroecosystem degradation. With the perception of urgency to reduce biotic stress sustainably, the present study was undertaken. Four native rhizospheric microbes: Trichoderma lixii, T. brevicompactum and two strains of Bacillus subtilis, were evaluated for their antagonistic potential toward soil-borne and foliar pathogens of tomato under pot conditions. The data obtained revealed T. lixii as the most effective isolate, which substantially reduced the disease severity and promoted plant growth. In two consecutive pot experiments, T. lixii was observed to reduce the fusarium wilt and early blight severity by 32% and 31%; and 30% and 25%, respectively, compared to the untreated control. Moreover, T. lixii was reported to colonize the plant roots, which was evident from the result obtained for biofilm formation and spores colonization on root cells. TvR1 also improved the photosynthetic content of both infected and non-infected plants. The conclusion drawn from the result suggested that the native microbial rhizospheric isolate T. lixii was effective in ameliorating the biotic stress, which might be due to root colonizing ability, and therefore, it could be designed into a bioinoculant for green agriculture.

Increasing the income of crop growers per unit area and restoring the fertility of marginal soils are major challenges of agricultural sustainability in the Indian agrarian economy. This study investigates the benefits of plant communities consisting of Indian licorice (Abrus precatorius L.), stevia (Stevia rebaudiana B.), chilli (Capsicum annum L.), and a microbial consortium of four plant growth‐promoting bacteria and fungi (Bacillus pseudomycoides, Bacillus firmus, Aspergillus luchuensis, and Aspergillus tamarii) on production of plant biomass, income of growers, and its ability to improve soil fertility over a 2 year period. The three crop species were planted in all possible groupings at one, two, and three species diversity levels with three replication and two treatments, that is, with plant growth‐promoting microbes (PGPM) and without PGPM. The maximum increases in biomass (6.8 mega gram ha⁻¹) and aboveground carbon sequestration (3.2 mega gram ha⁻¹) were found for the three species diversity level of LSC (Indian licorice–stevia–chilli) plus PGPM. The highest belowground carbon sequestration (35 mega gram ha⁻¹) and maximum soil fertility benefits [for example, pH (1.16‐times), electrical conductivity (7.53‐times), bulk density (1.84‐times), soil total organic carbon (3.99‐times), available nitrogen (5.95‐times), dehydrogenase (6.16‐times), microbial biomass carbon (4.06‐times), and colony‐forming units (4.44‐times)] were recorded at the two species diversity level of LC (Indian licorice‐chilli) with and without PGPM, compared with the soil properties before cultivation of these plants/additives. The highest net income (9.9 Lac ha⁻¹ yr⁻²) was estimated for the two species diversity level (LS) plus addition of PGPM.