Vinayak V. Pathak

Experimental study for growth potential of unicellular alga Chlorella pyrenoidosa on dairy waste water: an integrated approach for treatment and biofuel production.

This communication presents an integrated approach to study the potential of Chlorella pyrenoidosa for treatment of dairy wastewater (DWW) and biofuel extraction. The experiment was set up in two steps. The step-1 of the experiment was designed for treatment of dairy wastewater. The physical and chemical parameters of wastewater quality such as nitrate, phosphate, chloride, fluoride, hardness, etc., were studied. The level of nitrate and phosphate known, agents of eutrophication in water bodies was reduced by 60% and 87% in influent, 49% and 83% in the effluent, respectively. The step-2 of the experiment was designed for biofuel extraction by harvesting the biomass (algal strain) grown in dairy waste water. The result of this study shows that algal strain C. pyrenoidosa is not only an agent for mitigation of pollutant load, but it can also be used as potential agent for biofuel production.

A novel method to harvest Chlorella sp. via low cost bioflocculant: Influence of temperature with kinetic and thermodynamic functions

In this study, harvesting efficiency (HE) of bioflocculant (egg shell) was observed with variation in flocculent concentrations (0-100mgL-1), temperature (30°C, 35°C 40°C, 45°C and 50°C) and variable contact time (0-50min). It was found maximum (≈95.6%) with 100mgL-1 bioflocculant concentration whereas influence of temperature was also observed with optimized concentration of bioflocculant (100mgL-1) at 40°C (≈98.1%) and 50°C (≈99.3%), in 30min of contact time. Significant changes in algal cell structures were also analyzed after exposure to various temperatures with microscopy, SEM (Scanning electron microscopy) and EDS (Energy dispersive X-ray spectroscopy) images with and without bioflocculant. The experimental data was found to be a good fit with pseudo-second order kinetic model. The thermodynamic functions such as ΔG (Gibbs free energy), ΔH (enthalpy), ΔS (entropy) were also determined. The negative value of ΔG and positive value of ΔH and ΔS shows the spontaneous and endothermic nature of flocculation process.

Microalgal cultivation for value-added products: a critical enviro-economical assessment

The present review focuses on the cultivation of algal biomass for generating value-added products (VAP) and to assess their economic benefits and harmful environmental impact. Additionally, the impact of bioreactor designs on the yield of microalgal biomass for VAP is also considered. All these factors are discussed in relation to the impact of microalgae production on the bio-economy sector of commercial biotechnology.

Prospects for pretreatment methods of lignocellulosic waste biomass for biogas enhancement: opportunities and challenges

ABSTRACT Lignocellulose biomass/lignocellulosic waste biomass (LCB/LCWB) represents the largest renewable pool for potentially fermentable carbohydrates, which provides a good solution for bioenergy production. Although it is assumed to have a lower theoretical yield for biogas than waste material made of sugar or starch, it is free from the problems associated with other generations of biofuels. An inexpensive and efficient pretreatment method of LCB/LCWB is highly desired to achieve an economical biogas production process. This paper reviews the conventional, advanced and infant (i.e. under development) pretreatment methods that have been studied for enhancement of biogas production. In addition to various pretreatment methods, this article also reviews further aspects of the conventional, advanced and infant methods (nanotechnolgy) for pretreatment of LCB/LCWB. Thus, the article provides systematic technological strategies and new pretreatment approaches for sustainable bioprocessing of LCB/LCWB into value-added product.