By JOJO DE GUZMAN
SCIENCE CITY OF MUÑOZ, Nueva Ecija - For the conversion of
rice stubble and straw to ethanol as an alternative to crude oil-based fuels,
lowly Philippine carabao might yet play an important role for the its commercial
production.
Dr. Fiorello Abenes, a professor emeritus of animal and
veterinary sciences at CalPoly Pomona University in California and who recently
gave a lecture at the Institute of Graduate Studies at the Central Luzon State
University here, said "The carabao is a paradigm in converting lignocellulose to
ethanol and provides the model, just like a 'mother liquor' in the conversion
process."
The Filipino-American scientist said the carabao "has rumen
fluid whose organisms can help transform rice stubble and straw and other
biomass into bioethanol".
Bioethanol is a light alcohol produced by fermenting
sugarcane, corn, cassava and nipa. It is one of the types of biofuel mandated
for mixture with diesel and gasoline under the Biofuels Act.
The theoretical basis for this was validated by experiments
conducted at the Philippine Carabao Center (PCC) here.
"The experiments confirmed the ability of the model to
produce ethanol using rumen microorganisms as first stage fermenters, followed
by yeasts in the final fermenting stage," he said.
Abenes graduated with the degree of agricultural education,
cum laude, from the CLSU in 1969. He was among the first Filipinos staying
abroad who responded to the government's Balik-Scientist program in 1975.
He obtained his doctoral degree in animal science at the
University of Connecticut in 1975, where he worked for many years as regional
swine specialist in Alberta, Canada and at the Dairy Training and Research
Institute of the Food and Agriculture Organization of the United Nations before
moving to CalPoly Pomona University.
He retired at 55 years old in that university in 2005 and is
now engaged in various private enterprises in the United States.
In his lecture he said "we can extract the rumen fluid from
carabao and multiply them many times for commercial production of ethanol from
biomass". Abenes said the carabao is a model for a way to convert lignocellulose
to ethanol. Lignocellulose is the most common molecule on earth and is found in
all plants.
Converting this molecule to alcohol using purified enzymes,
chemical and physical hydrolysis (or chemical breakdown) is too expensive under
Philippine conditions, Abenes said.
"The carabao is known for its ability to subsist on low
quality forage, including rice stubble and straw. This ability is conferred upon
this animal by the rumen that digests cellulose and hemicellulose, turning them
into methane and volatile fatty acids (VFAs)," Abenes said.
Abenes said the methane is expelled when the carabao belches
while the VFAs are parceled between the host animal and the microorganisms. "The
host animal uses the VFAs as a source of energy. The microorganisms use them to
support its life functions by synthesizing glucose," he said.
Abenes said the feasibility of the method has been validated
in experiments conducted with PCC scientist Perla Florendo and because of the
promising results of the experiment they submitted a paper to a national science
and technology contest in energy research and development.
He said the rumen fluid can turn lignocellulose into
fermentable carbohydrates and the fermentable carbohydrates can be turned into
alcohol using common yeast.
"We have no illusion about winning any prize due to limited
scope of the project but its submission at least documents that the first
research in this area was conducted at PCC and CLSU," Abenes added.
He said preliminary calculations based on theoretical models
have indicated that as much as 117 liters of alcohol can be distilled from 1,000
kg of biomass materials.
Sen. Miriam Defensor-Santiago, author of the Biofuels Act,
sought more government oversight powers over biofuel development, saying it
could adversely affect the country's ability to produce its own food.
She said biofuel production, being land-based, will
eventually compete with food.
Abenes said the carabao model for production of ethanol could
be an alternative as it uses rice straw and other biomass.
He cited the experience of Brazil, the oft-cited model for a
thriving ethanol industry, which cannot be replicated in this country. According
to Abenes, Brazil has a vast tract of land for sugarcane production.
There are less than 25 persons per square kilometer of land
in Brazil compared to the Philippines' 300 persons per square kilometer. Brazil,
the fifth largest country in the world, has a land area of 8,511,965 square
kilometers. The Philippines' land area is 300,439 square kilometers.
Abenes explained that the commercial production of ethanol
using the carabao model can involve residents of rural areas. They can be part
of the factory assembly line by performing the tasks involved in the digestion
process (in bioreactor containers) of the biomass material with the use of the
rumen fluid that will be supplied to them.
The alcohol from the "bacterial beer" collected from the
participating rural residents can be further refined through a solar distiller,
he said.
The distiller is now being designed by engineers also from
CLSU, he said.
Abenes also said residents who will be involved in this project can have
added income, making the project a boost to countryside development.
