Currently the alternative fuel favourite ethanol is king. Almost all ethanol produced in the United States is fermented from readily available sugars in corn. But Ethanol from corn has recently come under much criticism and has with some justification been accused of being responsible for rising food prices worldwide which have obviously impacted hard on third world countries. Isn’t it time therefore to be looking at other crops and also at waste products as a source of fuel – and if you have read the first article in this issue you will readily agree that there is enough waste available!
Researchers are now looking at alternate biomasses as food for microorganisms to ferment into ethanol. The most attractive are known as lignocellulosic biomass and include wood residues (including sawmill and paper mill discards), municipal paper waste, agricultural residues (including sugarcane bagasse) and dedicated energy crops (like switchgrass). The problem is, unlike corn, the sugars necessary for fermentation are trapped inside the lignocellulose. Researchers at the University of Puerto Rico have been looking at unusual ecosystems and unusual organisms to find enzymes to help extract these sugars. Govind Nadathur and his colleagues at the university comment that
“Wood falls into the ocean. It disappears. What’s eating this biomass? We found mollusks that eat the wood, with the help of bacteria in their stomachs that produce enzymes that break down the cellulose. We found something similar in termites.” They plan on using these enzymes as a key step in a closed, integrated system that would not only produce ethanol, but would also produce sugar, molasses, hibiscus flowers and biodiesel with a minimum of waste.
It all starts with sugar cane and hibiscus flowers, grown on local lands. These produce not only the obvious products such as refined sugar, molasses (which is used to make rum) and flowers, but also a large amount of waste in the form of biomass. Using the enzymes in their library, Nadathur and his colleagues could break down the biomass to sugars and ferment them to ethanol, trapping the carbon dioxide that is produced during fermentation. They then would feed the carbon dioxide to microalgae in ponds that would produce a polymer that could be refined into biodiesel or jet fuel. The spent microalgae could then be harvested and used as fertilizer for the next round of sugar cane and hibiscus, thereby closing the cycle.
“There used to be a booming sugarcane industry in Puerto Rico, but in the mid-1990s it died. It could not survive economically. By creating a closed-loop system that utilizes the waste to create additional products and feeds back upon itself, suddenly growing sugar cane becomes economically feasible again,” says Nadathur.
They are currently working with a company called Sustainable Agrobiotech of Puerto Rico to build a pilot program which they hope to have running by early 2009. Should the pilot program prove successful, there is plenty of adjacent farmland to upscale.

What other ideas are there to produce alternative biofuels?
Another promising biofuel is hydrogen. Already many car manufacturers are producing hydrogen concept cars and pilot programs using hydrogen-powered buses already are gaining acceptance in Los Angeles in the USA. As more buses come online, there will be a greater need for hydrogen. Unfortunately, current chemical manufacturing processes for hydrogen are not that efficient or use fossil fuels as a source.
However, Sergei Markov of Austin Peay State University has developed a prototype bioreactor that uses the purple bacterium Rubrivivax gelatinosus to produce enough hydrogen to power a small motor.
He says that certain purple bacteria, which usually grow in the mud of various ponds and lakes, have the ability to convert water and carbon monoxide into hydrogen gas. The problem was how to effectively supply each bacterial cell in a liquid bacterial soup with gaseous carbon monoxide.
The answer was found by attaching the bacteria to numerous tiny hollow fibres inside an artificial kidney cartridge. Water and gasses can freely diffuse through the fibres, but bacteria, due to their large size, are unable to pass through. The hydrogen gas from a small fifty millilitre “artificial kidney bioreactor” has been directly injected into fuel cells and has produced enough electricity to power small motors and lamps. The only drawback is that carbon monoxide is not readily available, but Markov says it can be easily produced from biomass using a specific thermo chemical process. Also, there are other bacteria that produce carbon monoxide.

The Holy Grail of Hydrogen Production?
One researcher and her lab, though, are investigating what could perhaps be considered the holy grail of hydrogen production: Pin Ching Maness of the National Renewable Energy Lab in Golden, Colorado, is researching cyanobacteria that harness the power of the sun to break the bonds in water, separating the hydrogen from the oxygen thus producing what could be termed the Holy Grail of Hydrogen production – pure hydrogen from only water and sunlight, with a little bacterial help. There is a problem. One of the hydrogenase enzymes the cyanobacteria uses in this process is sensitive to O2, which makes sustained hydrogen production extremely difficult.
In some very detailed research, they found that a certain purple bacterium uses a similar hydrogenase, but one that is tolerant to O2. Maness and her colleagues have identified the genes that the purple bacterium uses to produce the tolerant hydrogenase. They have also identified the genes a particular model cyanobacterium uses to produce the sensitive hydrogenase and have knocked it out. They are currently in the process of cloning the genes for the tolerant enzyme into the model cyanobacterium. The next step is to verify that the genes have been successfully incorporated into the genome and are expressed. Over the next few years additional research will need to be done to ensure all the requirements are there for the construction of an active hydrogenase enzyme.

Adapted from materials provided by American Society for Microbiology, via EurekAlert!, a service of AAAS.

Reference: American Society for Microbiology (2008, June 5). Are Microbes The Answer To The Energy Crisis?.

A new study of the potential ecological impact of various management strategies found that very little can be done to make palm oil plantations more hospitable for local birds and butterflies. The findings have major implications for the booming market in biofuels and its impact on biodiversity.

Dr Lian Pin Koh of ETH Zürich looked at the number of birds and butterflies in 15 palm oil plantations in East Sabah, Malaysia, on the island of Borneo. He found that palm oil plantations supported between one and 13 butterfly species, and between seven and 14 species of bird. Previous research by other ecologists found at least 85 butterfly and 103 bird species in neighbouring undisturbed
rain forest.

Management techniques — such as encouraging epiphytes, beneficial plants or
weed cover in palm oil plantations — increased species richness by only 0.4 species for butterflies and 2.2 species for birds. Preserving remaining natural forests — for example by creating forest buffer zones between plantations — made a little more impact, increasing species richness by 3.7 in the case of butterflies and 2.5 for birds.

According to Dr Koh: “Rapid expansion of oil palm agriculture onto forested lands, even logged forests, poses a significant threat to biodiversity. This study shows that to maximise biodiversity in oil palm plantations, the industry and local governments should work together to preserve as much of the remaining natural forest as possible, for example by creating forest buffer zones around
oil palm estates or protecting remaining patches of forest. Even then, the industry’s impact on biodiversity is enormous.” The study is particularly important because it comes at time when rising demand for both food and biofuels is putting mounting pressure on biodiversity. “The rapid expansion of oil palm agriculture in Southeast Asia raises serious concerns about its potential impact on the region’s biodiversity. Unless future expansion of oil palm agriculture is regulated, rising global demand is likely
to exacerbate the high rates of forest conversion in major oil palm-producing countries,” says Dr Koh.

Palm oil plantations currently cover around 13 million hectares worldwide, producing 40 million tons a year. Malaysia and Indonesia account for around 56% of this cultivated area and 80% of production. Between 1960 and 2000, global palm oil production increased 10-fold (from 2 million tons in 1960 to 24 million tons in 2000). As well as biofuel, palm oil is used in food additives, cosmetics
and industrial lubricants.

Reference:
Lian Pin Koh. Can palm oil plantations be made more hospitable for forest
butterflies and birds? Journal of Applied Ecology, 9 July 2008