Shamshad Ahmad

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.

Plant Growth Under Stress Conditions: Boon or Bane

Plants are very prone to various stress conditions due to excessive use of chemical-based products and impacts of various living organisms (bacteria, virus, fungi, etc.) with their natural environment. These stresses, if continued for a long period, may affect the growth of plant and productivity to a great extent. Among the various types of stress conditions associated with nutrient, water, soil, and climate-specific stresses can be categorized for better understanding the concept of adaptation in the changing environment. Different types of stresses affect the physiological or metabolic pathways in plants. Water stresses adversely impact the plant physiology especially photosynthetic capacity, drought affects water potential and reduces growth of the plants, excess of nitrogen may cause dehydration of plants, etc. Hence, with these stress conditions arising due to the changes in surrounding environment, plants adapt to different types of physiological, morphological, and genetic changes to ensure their existence on this planet. In the present chapter, different kinds of stresses and their tolerance and adaption mechanism by various plant groups have been discussed in general, but the main focus is given to the C3 and C4 plants in particular. Similarly, impacts of anthropogenic activities responsible for climatic changes or stresses will also be investigated with growth of plants in different habitats and their responses toward these stress conditions.