Current Biochemical Engineering (Discontinued) - Volume 3, Issue 1, 2016

There is the growing demand for biofuel and bio based energy due to the depletion of the conventional fossil based resources. Thus, the estimation of the current resources of these alternatives and their future availability become imperative to maintain a sustainable supply in the future. The information presented in this study was collected through an intensive search and consultation of existing databases, which was thereafter corroborated by coordinating with authenticated sources of several national and state level departments, universities, institutes and agencies. The set of information collected and compiled included biomass from three major sectors: forestry, agriculture and bio-wastes, in India. Based on the compilation of this secondary data, the results of the current study provide a general overview on the total biomass resources currently present and the surplus available in the country. This inventory of available biomass was carried out as one of the objectives of an Indo-EU networking initiative SAHYOG, indicated a substantial amount of biomass resource through agricultural residues and municipal solid waste. It also indicated that although India has a considerable amount of area under forest cover, this resource is largely untapped due to the current government policies. The study also showed that India could generate a total of 4506.04 MW biomass based energy and was provided to the national grid by mid-2013, which are due to the implication of the policy frameworks of the Indian government towards alternative energy sources. This study also tries to provide a comparative analysis of Indian bio-fuel policy with those existing in few other countries. Thus, the current study presents an overview, trend and availability of biomass along with the current status of bioenergy in India. This can form the basis to develop a roadmap for the transition towards a bio based economy in the country.

Organic wastes of cellulose or sugar materials are abundant. Their treatment or disposal is a big issue worldwide. To reach the treatment purpose, using a two-phase biohydrogen and biomethane production technology has been found to be effective for environmental protection and energy production. In this work, the feedstock characteristics, H2/CH4 producing microorganisms, process design, system operation strategy, energy and economic assessments are reviewed for fermentative hydrogen and methane productions from organic wastes. Wastewaters, liginocellulose and algae are potential biogas production feedstock. Two-phase of hydrogen and methane fermentation processes are well introduced for effective gaseous energy production. Clostridium is known as a dominant microflora for hydrogen production. Optimal control of hydraulic retention time, operation pH and temperature efficiently enhance biogas production. Energy assessment indicated that energy recovery efficiency is feedstock-dependent with sugary wastewater having the energy recovery of a hydrogen fermenter reached 50-60% of that of methane fermenter. A field plant of two-phase biofuel gas production process was introduced for elucidating on-site application of the technology. The economic analysis case study of condense molasses feedstock for a two-phase H2/CH4 production system showed that the internal rate of return (IRR) and payback were 32.5% and 3.2 years, respectively. Therefore, sugary wastewater is a potential feedstock for hydrogen and methane fermentation in future industrial application. Moreover, the ways of accelerating the realization of hydrogen economy for helping to solve global climate change were suggested.

The increasing consumption of energy, increasing demand for fossil fuels, escalating fuel prices, and rising levels of CO2 and other greenhouse gases are some of the factors contributing to the search for alternative sources of energy. As solar, wind, hydro and geothermal sources are attractive in providing electricity, they lack the ability to support the production of transportation fuels. This brings lignocellulosic biomass into limelight to sustain the supply of solid, liquid and gaseous biofuels. Lignocellulosic biomass is chemically composed of cellulose, hemicellulose and lignin that can be transformed into energy-dense components for use as fuels or chemicals. This review focuses on the various conversion technologies available for biomass conversion to biofuels. The two basic conversion routes discussed are thermochemical (pyrolysis, liquefaction, torrefaction and gasification) and biochemical (fermentative pathways). Compared to biochemical conversion that requires ambient conditions, thermochemical routes require the involvement of high temperatures and pressures for biomass conversion. The fuel products comprehensively discussed here are bio-oil, syngas, ethanol and butanol. Syngas fermentation has been presented as an advanced biomass conversion technology that converts syngas to higher alcohols in the presence of mesophilic and thermophilic microorganisms. Butanol, a progressive fuel than ethanol, is highlighted in terms of its biochemical production and fuel properties. Nevertheless, the review summarises the integration of thermochemical and biochemical conversion routes to efficiently produce the primary fuel product and utilize the co-products.

Fossil fuels are the primary source of energy production. However, owing to their negative effects and ever increasing demand of energy, biofuels, especially, biobutanol is gaining increased interest. At present, the biofuel market is dominated by biodiesel, bioethanol, biobutanol, and biogas, much relying on the substrates such as- sugars, starch, oil crops, agricultural and animal residue, and lignocellulosic biomass. Butanol (C4H9OH) has superior fuel properties over traditional fuel ethanol in terms of energy density and hygroscopicity. There are some bottlenecks that need to be overcome in the production of butanol in order to get a sustainable alternative for fossil fuels. Lignocellulosic biomass due to its low cost and yearlong availability, is a suitable raw material for butanol production. In this mini review, feedstock, microorganism, process modifications, and past and present trends in biobutanol production have been discussed. In this review, an attempt has been made to develop a better understanding about acetone-butanol-ethanol fermentation process.

Inclusion bodies (IBs) are often produced during overexpression of recombinant proteins in E.coli. These were initially perceived as amorphous aggregates of misfolded (and hence inactive) protein molecules. It turns out that in many cases, IBs contain varying amount of native like structures and show different extent of biological activity. At the same time, IBs perhaps differ only qualitatively from amyloids in having β-sheet structures. It seems likely that precipitates, IBs and amyloids represent different trade off points to achieve thermodynamic stability at the cost of biological activity.

Confocal laser scanning microscopy (CLSM) as an innovative technique has been widely used in biological research and it offers unique opportunities to visualize distribution and transportation of proteins in various media. For protein chromatographic purification studies, CLSM can further provide direct and detailed information about protein adsorption behaviors. This review highlighted the application of CLSM in investigating protein adsorption processes including single-component and multi-component studies in finite bath adsorption and real-time observation of protein adsorption in the micro-column with various adsorbents. Factors such as liquid phase conditions and the limitation of CLSM application in protein adsorption were discussed. The adsorption profiles in different adsorbents, such as the widely observed shrinking core profile, the overshoot adsorption profile as well as some special profiles were compared and discussed.

There are many tests published on the methane yield of cattle manure, both using batch tests with inoculum and tests with continuously stirred tank reactors [CSTR]. These tests have a variation in methane yield of 130 - 300 l/kg volatile solids [VS], influenced by the freshness of the manure, diet of the cattle (composition of the manure), temperature of digestion, the type of inoculum, ratio between inoculum and manure, solids content and the length of the testing period. In most cases only a few of these parameters have been documented.