Bioprocessing strategies for biobutanol production from agricultural wastes

Interest in producing renewable biofuel such as biobutanol to replace demand on non-renewable petrol fuel showed an increasing trend in recent years. Many researchers are investigating numerous approaches in order to produce biobutanol at a low cost. Such efforts are by considering suitable feedstock materials and bioprocessing technologies. Renewable materials such as starch, lignocellulosic, and algal biomass are some of the common feedstocks utilized for biobutanol production, and each of them has their own advantages, yet possess several disadvantages that need improvement. Low sugar concentration generated from hydrolysis of biomass, inefficient microorganism and unsuitability of conventional batch fermentation have been noted as the main reasons for a low biobutanol yield and productivity. Therefore, several fermentation operations and integrated bioprocessing technologies have been developed to improve the biobutanol production efficiency. The challenges and the appropriateness of the technologies on different types of agricultural wastes are being presented in this talk

Lignocellulosic biofuel: a way forward

Economic dependency on fossil fuels and the resulting effects of its usage on the environment has placed considerable focus on utilizing biosugars from lignocellulosic biomass, the largest known renewable carbohydrate source as an alternative. Biosugars are derived from cellulose and hemicelluloses constituents; however these are in turn not readily accessible to enzymatic hydrolysis and hence requiring pretreatment, for extensive modification of the lignocellulosic structure. A number of pretreatment technologies are currently under development and tested at pilot scale. Hydrolysis of lignocellulose into biosugars requires a number of different cellulases and hemicellulases. The hydrolysis by cellulases is a sequential breakdown of the linear glucose chains, whereas hemicellulases must be capable of hydrolysing branched chains containing different sugars and functional groups. The technology for pretreatment and hydrolysis has been developed to an extent that is close to a commercially viable level. For example, processing of lignocelluloses at high substrate levels have become possible, all the while with improvements made on enzyme performances. In addition, the cost of enzymes has also been reduced. Nevertheless, a number of technical and scientific issues within pretreatment and hydrolysis remain to be solved and with significant expected improvements in yield and cost reductions, large-scale fermentation of lignocellulosic biomass is conceived to be possible. The concept of producing lignocellulosic biofuel, bioproducts and chemical through a biorefinery using lignocellulosic biomass had been around for 70 years or more. The use of renewable energy resources has become essential at a time when the focus is on global warming, carbon dioxide emission, security of energy supply, and reduction in consumption of fossil-based fuels. The recent interest in this biorefinery concept is based on the mitigation of climate change by substituting the biomass energy for petroleum or other fossil-fuel energy. Thus the realization of biorefinery concept remains a challenge

Biovanillin from agro wastes as an alternative food flavour

This review provides an overview of biovanillin production from agro wastes as an alternative food flavour. Biovanillin is one of the widely used flavour compounds in the foods, beverages and pharmaceutical industries. An alternative production approach for biovanillin as a food flavour is hoped for due to the high and variable cost of natural vanillin as well as the limited availability of vanilla pods in the market. Natural vanillin refers to the main organic compound that is extracted from the vanilla bean, as compared to biovanillin, which is produced biologically by microorganisms from a natural precursor such as ferulic acid. Biovanillin is also reviewed as a potential bioflavour produced by microbial fermentation in an economically feasible way in the near future. In fact, we briefly discuss natural, synthetic and biovanillin and the types of agro wastes that are useful as sources for bioconversion of ferulic acid into biovanillin. The subsequent part of the review emphasizes the current application of vanillin as well as the utilization of biovanillin as an alternative food flavour. The final part summarizes biovanillin production from agro wastes that could be of benefit as a food flavour derived from potential natural precursors

Optimization of vanillic acid production by Pseudomonas sp. AZ10 UPM using statistical analysis approach

The world market demand of vanillin could not totally supply through natural extraction, chemical synthesis, or tissue culture technology. Biotechnological approaches provide an alternative route to produce biovanillin economically viable such as the microbial conversion pathway. Research has shown that agro-waste containing ferulic acid, such as oil palm empty fruit bunch (OPEFB) can be used to produce vanillin. However, the vanillin is rapidly converted to vanillic acid which is the less toxic form. The present work describes the screening of microbial strains capable of degrading ferulic acid as sole carbon source and optimization of fermentation conditions for the enhancement of vanillic acid production. Vanillic acid can then be used as a precursor for vanillin production. From this study, the potential isolate was selected based on the ability of the strain to grow on ferulic acid, highest intensity of colour changes on rapid screening plate, and subjected to fermentation for vanillin and vanillic acid quantification. The strain Pseudomonas sp. AZ10 UPM exhibited a significant result because of colour changes observed on the assay plate on day 1 with a high intensity of yellow colour. Then, optimization was carried out by screening four factors namely pH, temperature, concentration of synthetic ferulic acid, and percentage of inoculum with main and interaction effects evaluated using Design Expert® software. The optimal yield of vanillic acid obtained were at pH 7, incubation temperature of 31 °C, 1.5 g/L synthetic ferulic acid, and 10% inoculum size with molar conversion yield of 75%

Biological pretreatment of lignocellulosic biomass for volatile fatty acid production

Volatile fatty acid (VFA) platform has been suggested as a potential alternative to sugar platform for the production of biofuels and fine chemicals. Biomass-derived VFA is one of the potential alternatives for VFA production that required only a mild pretreatment process to open up the lignocellulosic biomass structure for anaerobic digestion (AD), whereas some of the biomass like food waste, manure, sludge, or any biodegradable biomass do not require any pretreatments. Lignocellulosic biomass such as hardwood (forestry and agricultural biomass) does require pretreatments to remove lignin or to alter the lignocellulosic compositions. Besides, VFA also can be produced from all types of organic polymers (carbohydrates, protein, and lipid) that will increase the VFA yield as compared with sugar platform, which can be produced from carbohydrate polymers only. Biological pretreatment of lignocellulosic biomass offers an advantage for the production of VFA. This chapter will focus on suitable pretreatment strategies for VFA production especially on the biological pretreatments

Storage stability of clarified banana juice fortified with inulin and oligofructose.

Clarified banana juice fortified with inulin and oligofructose were stored for 8 weeks at 4, 25 and 35C. Changes in physicochemical characteristics (pH, total soluble solids [TSS], titratable acidity, sucrose, reducing sugars and turbidity), microbial count and sensory quality were determined. No differences were observed for pH and titratable acidity for all the stored juice samples. However, increase in turbidity was observed in all the juice samples, whereas juice samples stored at 35C recorded highest increases. Increase in reducing sugars (glucose and fructose) was also observed during storage, particularly at 25 and 35C. TSS values were observed fluctuating for all the samples. No microbial growth was recorded for all the juice samples stored at three different temperatures. Sensory results for taste, flavor and odor revealed no difference until the seventh week of storage; however, the overall acceptability of the juice stored at 4C was rated highest as compared with juice samples stored at 25 and 35C. Overall, the quality of juice stored at 4C was rated highest not only for all the sensory characteristics but also less turbidity problem compared with juices stored at 25 and 35C

Feasibility study on the extraction methods of essential oil from pineapple peels

The pineapple industry produces a substantial amount of solid waste like peels, cores, stems, crowns and pulp. Pineapple waste disposal can cause to microbial spoilage and environmental problems due to the waste material containing high moisture and sugar content. Utilization of pineapple waste, focusing on the peels, to produce a high value added product of essential oil is a good option. However, up to date, there are only a very limited studies specifically aimed on the extraction methods of essential oil from pineapple peels. Therefore, the aim of this study was to demonstrate a feasible method for extraction of essential oil from pineapple peels. Three methods used in the study were (1) hydro- distillation (HD), (2) hydro-distillation with enzyme-assisted pretreatment (HDEA) and (3) supercritical fluid extraction (SFE). Among the methods used, only SFE method resulted in the formation of essential oil with 0.17% (w/w) yield, whereas HD and HDEA methods only produced the hydrosol. The microscopic observation using scanning electron microscope of the sample’s cell wall substantiated that only SFE method resulted in the rupture the essential oil gland after the extraction. The GC-MS analysis showed that volatile compounds mainly identified in the essential oil produced through SFE method were propanoic acid ethyl ester (40.25%), lactic acid ethyl ester (19.35%), 2-Heptanol (15.02%), 3-Hexanone (2.60%) and butanoic acid ethyl ester (1.58%). The analysis results show that pineapple peels contained of important volatile compounds, thus indicating its’ potential to be used as substrate for the aromatic essence production

Methane capture and clean development mechanism project for the sustainability of palm oil industry in Malaysia

Anaerobic treatment with methane capture for the Clean Development Mechanism (CDM) project is currently the most promising treatment method for palm oil mill effluent (POME). With CDM, Annex 1 countries could achieve their greenhouse gases (GHG) emission reduction target, promoting environmental-friendly and sustainable development projects and providing substantial local economic and social sustainability and demonstrate and disseminate new and modern bio-energy technology with lower investment costs and risks by establishing partnership with host countries like Malaysia. As at end of March 2009, there were 12 methane recovery CDM projects in Malaysia registered with the Executive Board (EB) of United Nation Framework on Climate Change (UNFCCC), which expecting to contribute an annual average of 612,097 tonnes of CO2 equivalent of certified emission reductions (CER). Although this is small despite the huge potential available, the trend is growing. Therefore Annex I countries should urgently take this opportunity to be actively involved in this new business opportunity for the sustainability of the palm oil industry

Biobutanol production from sago hampas through simultaneous saccharification and fermentation by Clostridium acetobutylicum ATCC 824

The mounting prices of the current gasoline have driven the attention of researchers towards the utilization of various biomass residue for the production of biobutanol as it has a superior fuel characteristic. Sago hampas contains starchy and lignocellulosic materials that is usually discharged to the nearby river without a proper treatment. It is composed of 54.6% starch and 31.7% of cellulose and hemicellulose with only 3.3% of lignin. High carbohydrate contents with low percentage of lignin and no pretreatment process is required, make the sago hampas as a promising feedstock for biobutanol production. Simultaneous saccharification and acetone-butanol-ethanol (ABE) fermentation approach which is the conjoint addition of glucoamylase and cellulase together with microorganism and biomass in a single vessel system is carried out in order to reduce step, cost and time in biobutanol production. In this study, the saccharification of sago hampas is done using Dextrozyme amylase and Acremonium cellulase. The simultaneous saccharification and fermentation (SSF) of sago hampas conducted at the conditions needed for ABE fermentation by Clostridium acetobutylicum ATCC 824 produced 3.81 g/L biobutanol concentration and yield of 0.11 g/gsugar. In this study, it suggested that sago hampas possess great potential to be implemented for biobutanol production using the simultaneous system integrated two different processes of saccharification and fermentation