Ganapathy Sivakumar

Bioethanol and biodiesel: Alternative liquid fuels for future generations

The global population is expected to increase by approximately 3 billion people by 2050. With this increase in population, industry, transportation the cost of fossil fuels will grow dramatically. New technologies are needed for fuel extraction using feedstocks that do not threaten food security, cause minimal or no loss of natural habitat and soil carbon. At the same time, waste management has to be improved and environmental pollution should be minimized or eliminated. Liquid biofuels such as lignocellulosic‐based ethanol from plant biomass and algal‐based biodiesel are sustainable, alternative biofuels that could stabilize national security and provide clean energy for future generations. Ideally, the technology should also foster recycling of agricultural feedstocks and improve soil fertility and human health. This article provides updated information on the energy potential and breadth of liquid biofuel biotechnology.

Integrated green algal technology for bioremediation and biofuel

Sustainable non-food energy biomass and cost-effective ways to produce renewable energy technologies from this biomass are continuously emerging. Algae are capable of producing lipids and hydrocarbons quickly and their photosynthetic abilities make them a promising candidate for an alternative energy source. In addition, their favorable carbon life cycle and a renewed focus on rural economic development are attractive factors. In this review the focus is mainly on the integrated approach of algae culture for bioremediation and oil-based biofuel production with mention of possible other value-added benefits of using algae for those purposes.

Induced biosynthesis of resveratrol and the prenylated stilbenoids arachidin-1 and arachidin-3 in hairy root cultures of peanut: effects of culture medium and growth stage.

Previously, we have shown that hairy root cultures of peanut provide a controlled, sustainable and scalable production system that can be induced to produce stilbenoids. However to leverage peanut hairy roots to study the biosynthesis of this polyphenolic biosynthetic pathway, growing conditions and elicitation kinetics of these tissue cultures must be defined and understood. To this end, a new peanut cv. Hull hairy root (line 3) that produces resveratrol and its prenylated analogues arachidin-1 and arachidin-3 upon sodium acetate-mediated elicitation was established. Two culture media were compared for impact on root growth and stilbenoid biosynthesis/secretion. The levels of ammonium, nitrate, phosphate and residual sugars were monitored along growth and elicitation period. A modified MS (MSV) medium resulted in higher root biomass when compared to B5 medium. The stilbenoid profile after elicitation varied depending on the age of the culture (6, 9, 12, and 15-day old). After elicitation at day 9 (exponential growth in MSV medium), over 90% of the total resveratrol, arachidin-1 and arachidin-3 accumulated in the medium. Our studies demonstrate the benefits of the hairy root culture system to study the biosynthesis of stilbenoids including valuable prenylated polyphenolic compounds.

Bioethanol production from dedicated energy crops and residues in Arkansas, USA

Globally, one of the major technologic goals is to achieve cost-effective lignocellulosic ethanol production from biomass feedstocks. Lignocellulosic biomass of four dedicated energy crops [giant reed (Arundo donax L.), elephantgrass (Pennisetum purpureum (Schumach), Miscanthus × giganteus (Illinois clone), and (clone Q42641) {hybrid of Miscanthus sinensis Anderss. and Miscanthus sacchariflorus (Maxim)}, Hack. called giant miscanthus, and sugarcane clone US 84-1028 (Saccharum L. spp. hybrid)] and residues from two crops [soybean (Glycine max (L.) Merr.) litter and rice (Oryza sativa L.) husk] were tested for bioethanol production using cellulose solvent-based lignocellulose fractionation (CSLF) pretreatment and enzymatic (cellulase) hydrolysis. Giant miscanthus (Illinois), giant reed, giant miscanthus (Q42641), elephantgrass, and sugarcane all yielded higher amount of glucose on a biomass dry weight basis (0.290-0.331 g/g), than did rice husk (0.181 g/g) and soybean litter (0.186 g/g). To reduce the capital investment for energy consumption in fermentation, we used a self-flocculating yeast strain (SPSC01) to ferment the lignocellulosic biomass hydrolysates. Bioethanol production was ∼0.1 g/g in dedicated energy crops and less in two crop residues. These methods and data can help to develop a cost-effective downstream process for bioethanol production.

Biomass Production of Hairy Roots of Artemisia annua and Arachis hypogaea in a Scaled-Up Mist Bioreactor

Hairy roots have the potential to produce a variety of valuable small and large molecules. The mist reactor is a gas phase bioreactor that has shown promise for low‐cost culture of hairy roots. Using a newer, disposable culture bag, mist reactor performance was studied with two species, Artemisia annua L. and Arachis hypogaea (peanut), at scales from 1 to 20 L. Both species of hairy roots when grown at 1 L in the mist reactor showed growth rates that surpassed that in shake flasks. From the information gleaned at 1 L, Arachis was scaled further to 4 and then 20 L. Misting duty cycle, culture medium flow rate, and timing of when flow rate was increased were varied. In a mist reactor increasing the misting cycle or increasing the medium flow rate are the two alternatives for increased delivery of liquid nutrients to the root bed. Longer misting cycles beyond 2–3 min were generally deemed detrimental to growth. On the other hand, increasing the medium flow rate to the sonic nozzle especially during the exponential phase of root growth (weeks 2–3) was the most important factor for increasing growth rates and biomass yields in the 20 L reactors. A. hypogaea growth in 1 L reactors was µ = 0.173 day−1 with biomass yield of 12.75 g DW L−1. This exceeded that in shake flasks at µ = 0.166 day−1 and 11.10 g DW L−1. Best growth rate and biomass yield at 20 L was µ = 0.147 and 7.77 g DW L−1, which was mainly achieved when medium flow rate delivery was increased. The mist deposition model was further evaluated using this newer reactor design and when the apparent thickness of roots (+hairs) was taken into account, the empirical data correlated with model predictions. Together these results establish the most important conditions to explore for future optimization of the mist bioreactor for culture of hairy roots. Biotechnol. Bioeng. 2010;107: 802–813.

Bioprocess and bioreactor: next generation technology for production of potential plant-based antidiabetic and antioxidant molecules.

Globally, diabetes and obesity are two of the most common metabolic diseases of the 21(st) century. Increasingly, not only adults but children and adolescents are being affected. New approaches are needed to prevent and treat these disorders and to reduce the impact of associated disease-related complications. Industrial-scale production using plant-root cultures can produce quantities and quality of inexpensive bioactive small molecules with nutraceutical and pharmaceutical properties. Using this approach, and targeting these diseases, a next generation approach to tackling this emerging global health crisis may be developed. Adventitious roots cultured in bioreactors under controlled and reproducible conditions have been shown effective for production of natural products. The liquid-phase airlift bioreactor in particular has been used successfully for culturing roots on an industrial-scale and thus may provide an economical production platform for expressing promising plant-based antidiabetic and antioxidant molecules. This review focuses on a next-generation, scalable, bioprocessing approach for adventitious and hairy root cultures that are a pesticide-free, seasonally-independent, plant-based source of three molecules that have shown promise for the therapeutic management of diabetes and obesity: corosolic acid, resveratrol and ginsenosides.

Plant-based corosolic acid: future anti-diabetic drug?

Diabetes is one of the nations most prevalent, debilitating and costly diseases. For diabetes, frequent insulin treatment is very expensive and may increase anti‐insulin antibody production, which may cause unwanted side effects. Corosolic acid may also have some efficacy in the treatment of diabetes, but without induction of anti‐insulin antibodies. Recently, corosolic acid from Lagerstroemia speciosa L. leaf extracts has been reported to act via an indirect mechanism (unlike insulin) in animal experiments. The insulin‐complementary anti‐diabetic therapeutic value observed in these Japanese preliminary clinical trials has led to renewed interest in the biosynthesis of this compound. So far, there has been no clear evidence for a corosolic acid biosynthetic pathway in plants. This article provides possible roles of corosolic acid and hypothetical information on the biosynthetic pathway in plants.

Olive Biophenols and Conventional Biotechnology from Mediterranean Aliment Culture

The Mediterranean diet is a sort of therapeutic way to reduce developing cardio- and cerebro-vascular pathologies and degenerative diseases, cancer and aging, but does not reflect the eating habits of the Mediterranean population. The Portulaca oleracea used in salads, omelettes and potato dumplings contains eicosapentaenoic acid, a ω-3 fatty acid, in extraordinary amounts relative to other plant sources and normally found in fish and algae. Evoo and otos biomolecules are vital to Mediterranean culture for nutritional benefit and excellent eating quality, within the hedonic-sensory descriptors of modern functional food for aroma, odor, taste, texture, and convenience. The evoo and otos phytomolecules are influenced by agronomics, genomics, proteomics, pre- and post-harvest techniques, and processing, before reaching the table as Mediterranean traditional recipes. Complex bio - and techno -molecules in olive functional products are significant in determining cru and cuvee characteristics of evoos and otos . Some are largely responsible for the strong, fragrant, bitter, and pungent character of Mediterranean dishes, because of volatile aldehydes, ketones, aliphatic acids, and non-volatile secoiridoid-( seco )-monoterpenes. The phytomolecular mechanisms of soluble BPs and seco -BPs in bio - and techno -processes provide insights to improve olive-growing and olive-mill and storage technology for the best competitive quality of final products and a positive effect on the MAC food chain, as consumers, better informed about well-being and health aspects, are more demanding in product purity, quality, and territorial identity.