By Henrylito D. Tacio
The impact of ideas can be truly transformative.
Consider tilapias, known for their high reproductive rates. These fish reproduce regularly, typically every 30 days. A female tilapia can lay anywhere from 100 to several thousand eggs, depending upon her size.
If a fishpond is overcrowded, there is a likelihood that the fish will not achieve the anticipated size and growth. Is it feasible and possible to grow an all-male tilapia population in a pond without resorting to the labor-intensive process of manual sexing?
Studies have shown that the male tilapia grows faster and bigger than the female tilapia. The logical choice was to grow all male tilapias.
“In female tilapia, the energy that is supposed to be used for somatic growth is instead utilized for producing eggs for reproductive purposes and behavioral interactions,” wrote Rizza B. Ramoran in a press release disseminated by Science and Technology Media Services.
Rice straws are either burned or just left in the open field. (Photo by Henrylito Tacio)
Because of this, the University of the Philippines Visayas (UPV) launched a project that optimizes and develops an efficient protocol to produce male tilapias, or those that bear YY chromosomes.
The project, “Molecular Marker Assisted YY Male Tilapia Production,” is being funded by the Philippine Council for Agriculture, Aquatic and Natural Resources Research and Development (PCAARRD), a line agency of the Department of Science and Technology (DOST).
Right now, commercially available all-male tilapia fingerlings are produced through the use of steroid hormones. However, through this project, YY males (or super males) are being developed and will eventually be rolled out to tilapia farmers, allowing them to produce all-male (XY) tilapia progenies through natural breeding.
In genetics, pairing females (XX) with males (XY) produces a mix of XX and XY offspring. In this project, the XY males undergo a feminization process through oral hormonal ingestion to develop sex-reversed (SR) females with XY chromosomes. These SR females (XY) will then be used to mate with a natural male (XY) to produce male offspring with YY chromosome. With the availability of sex-linked DNA markers, the generation/selection and identification of YY males could be done more efficiently.
The identified YY males will then be mated with SR XY females. Their offspring will undergo another sex-reversion through hormonal ingestion, this time, to generate a female tilapia with YY chromosome. Once these SR YY female tilapias are identified, they will be mated with the YY male to generate all YY male offspring.
These YY male will be mass-produced to serve as broodfish and will be distributed to tilapia hatchery operators. YY male being parent stock are expected to mate with natural females (XX) to generate all-male (XY) tilapia offspring without the use of steroid hormones.
Instead of burning rice straw or leaving them on the field to rot, why don’t Filipino farmers convert the methane that rice straw produces and use it to produce clean fuel?
Tilapia can grow to the desired size if they are raised in an all-male environment. (Photo by Henrylito Tacio)
That’s what Dr. Craig Jamieson is doing at Los Baños, Laguna. His company, Straw Innovations (SI), Ltd., established the Rice Straw Biogas Hub, which generates biogas as clean energy from waste rice straw and provides an innovative package of technology services for rice farmers.
The clean fuel is used for drying the grains and milling thereafter. “We asked farmers and their preference was to use the energy for productive purposes rather than domestic use. So, that’s what we are doing,” says Dr. Jamieson, a British national who’s originally trained in horticulture and has a master’s degree in international rural development.
According to Jamieson, his United Kingdom-registered group has established a rice drying service through the combustion of biogas from rice straw.
Drying is the most critical operation after harvesting a rice crop. When rice is harvested, it contains up to 25% moisture. The goal of rice drying is to reduce its moisture content to meet the recommended levels for sale, long-term storage.
“It is important to dry rice grain as soon as possible after harvesting – ideally within 24 hours,” IRRI explained. “Delays in drying, incomplete drying or ineffective drying will reduce grain quality and result in losses.”
But before drying, rice has to be harvested first. Here, the SI introduced a rice harvesting system that has been developed over five years. “The main problems are in getting the rice straw out of the field and to a place where it can be used,” he said.
Rice straw after harvesting. (Photo by Henrylito Tacio)
The likely solution: the 5-in-1 harvesting technology, referring to a machine, which is said to be the first of its kind in the world. “Our machine performs in one pass of the field and performs the five separate operations in conventional straw collection – harvester, chopper, rake, densifier, and collection. It’s more efficient and, critically, it works even in wet conditions (muddy or flooded fields),” Dr. Jamieson pointed out.
The collected palay is then brought to another machine where the grain is separated from the rice straw. “At the biogas hub, a dryer dries the rice grain with energy from the rice wastes, another removes the husk and another mills the grain, thus giving the final product,” Dr. Jamieson said.
The dryer takes about 12 hours for the grain to dry, Jamieson said. “The technology innovation is to use rice straw to power the process,” he said. “We give farmers the option to retain ownership of their grains throughout the process.
“In some of today’s cases, farmers only get 4% of the purchase price of rice. In our model, farmers can use our harvesting, drying, and milling services and then sell the finished products to the public. We just take our cut after the sale…”
To produce methane in the hub, water is added with the rice straw. The methane gas is a direct substitute for diesel or kerosene in conventional dryers.
“In the past, the government tried to give out free rice dryers but as soon as something broke, the dryers were no longer used,” Dr. Jamieson said. “Our business model is to operate our equipment and offer it as a service to farmers. They pay us a service fee but don’t need to buy or operate our equipment.”
During the process, the rice straw gets broken down into fertilizer, which can be used to fertilize the rice. Or it can be applied as organic fertilizer for crops, vegetables, and fruits. “It can be used for anything,” he said.
The British innovator believed the biogas hub can prevent the burning of millions of tons of rice straw as waste across the region each year. “The hub has exciting potential to bring clean energy access to the 150 million small-scale rice farmers who need it to process their crops and generate new income opportunities,” he said.
Another technology that emerged from an idea: turning waste crab shells into diffraction gratings. That may sound so scientific but researchers from the Ateneo de Manila University (ADMU) are trying to do that.
The blue swimming crab (BSC) or alimasag is one of the most popular crab species. The Philippines is the fourth-largest producer and the third-largest exporter of this species to the United States, according to the Seafood Watch.
Shells and appendages make up 60% to 70% of the total weight of the BSC. Studies have shown that for every ton of crabs processed in a day, some 300-400 kilos of shells are dumped. All these wastes end up in landfills and some into the sea.
Yet, these wastes contain some of the most useful compounds in industrial settings that can be both profitable and sustainable. “Repurposing crab waste as a raw material for bioplastic components shows promise, with shells having chitin content of 10% to 72%, suitable for chitosan extraction,” said the ADMU researchers.
The researchers – Efren G. Gumayan, Ian Ken D. Dimzon, and Raphael A. Guerrero – managed to convert an extract from crab shells into a bioplastic that can be used to make optical parts known as diffraction gratings.
“Diffraction is the bending of light around an obstacle,” explained Dr. Gumayan. “A diffraction grating is an optical component that redirects light in specific directions based on its color.”
Diffraction gratings are oftentimes used in lasers, wavelength division multiplexing (a fundamental building block of modern telecommunications) and spectrometers.
The outer skeleton of crabs contains chitosan. “We wanted to find an alternative use for crab shell waste and decided to find out if chitosan from crab shells could be used as a biodegradable replacement for silicone, which we have previously used in our lab to make diffraction gratings,” said Dr. Guerrero.
“Gratings made of chitosan are biodegradable and environmentally friendly while also being very inexpensive since crab shells are generally considered waste,” Dr. Guerrero pointed out. “By showing that useful optical components can be made from materials typically considered waste, we hope to help improve sustainability in optical manufacturing and reduce the amount of seafood waste that requires disposal.”
