Microbial diversity and genomics in aid of bioenergy

Abstract

In view of the realization that fossil fuels reserves are limited, various options of generating energy are being explored. Biological methods for producing fuels such as ethanol, diesel, hydrogen (H2), methane, etc. have the potential to provide a sustainable energy system for the society. Biological H2 production appears to be the most promising as it is non-polluting and can be produced from water and biological wastes. The major limiting factors are low yields, lack of industrially robust organisms, and high cost of feed. Actually, H2 yields are lower than theoretically possible yields of 4 mol/mol of glucose because of the associated fermentation products such as lactic acid, propionic acid and ethanol. The efficiency of energy production can be improved by screening microbial diversity and easily fermentable feed materials. Biowastes can serve as feed for H2 production through a set of microbial consortia: (1) hydrolytic bacteria, (2) H2 producers (dark fermentative and photosynthetic). The efficiency of the bioconversion process may be enhanced further by the production of value added chemicals such as polydroxyalkanoate and anaerobic digestion. Discovery of enormous microbial diversity and sequencing of a wide range of organisms may enable us to realize genetic variability, identify organisms with natural ability to acquire and transmit genes. Such organisms can be exploited through genome shuffling for transgenic expression and efficient generation of clean fuel and other diverse biotechnological applications.

Production of Polyhydroxyalkanoate Co-polymer by Bacillus thuringiensis

“…Initially, methane generation alone was found to be the only aspect of waste/wastewater treatment through anaerobic digestion. However, it was soon realized that to make the whole process economical, we need to derive other products as well such as H 2 and PHB [1,5]. Efforts to produce H 2 , PHB and methane in different stages from the same feed have been found to be feasible [13,[17][18][19].…”

“…In order to circumvent this limitation of PHB, various studies have revealed that copolymers are better materials in terms of their crystallinity, molding and ductility [2,6,20]. Previously, a few photosynthetic organisms: Rhodopseudomonas palustris, Rhodospirillum rubrum and Rhodobacter sphaeroides were the only organisms known to produce both the bioproducts [1,4,5]. Bacillus spp.…”

“…Two major issues related to fossil fuels are their polluting nature and rapid depletion of their reservoirs [1]. The need is to look for non-polluting fuels and curtail the use of fossil fuels.…”

Hydrogen and Polyhydroxybutyrate Producing Abilities of Bacillus spp. From Glucose in Two Stage System

“…Environmental pollution caused by wastes and rapid depletion of fossil fuels are issues of prime concern [1].…”

“…Degradation of biowastes to methane (CH 4 ) and carbon dioxide is a multiple step process with possibilities to produce H 2 and bioplastics (from volatile fatty acids) as intermediates [1,5]. The whole process is becoming attractive on account of higher production efficiency, stability and economic feasibility [6].…”