The biomass from forestry, range and grasslands, agricultural wastes and crop residues is the most abundant renewable biomass on earth with a total annual production in the tens of billions of metric tonnes. About four billion of those tonnes come from crop residues, which are the major feed resource in most of the livestock systems where ILRI works. Unfortunately, crop residues, particularly of cereals, make poor fodder, and animals fed solely on them rarely thrive. Improving the fodder quality of crop residues is nothing less than a game changer in livestock feed resourcing.

Although a biomass called lignocellulosic is not digestible in humans and most monogastrics, in essence, it is not all that different from the starch found in grains and cereals. In fact, embedded in the walls of many plant cells are hexose and pentose sugars. However, these sugars are locked into complex chains of carbohydrates and lignins that make them inaccessible to most mammalian digestive systems. Those chains are so tightly bound that even the microbes hosted by ruminants can access only a fraction of the potential nutritive energy contained in the biomass.

The technology may provide a way for farmers in specific areas of the Indo-Gangetic Plain to dispose of rice straw without burning it.

An almost limitless potential

For these two reasons—the almost limitless quantities of the stuff and its potential as an energy source—scientists have been trying since the start of the 20th century to upgrade lignocellulosic biomass for livestock fodder. And for those same reasons, other scientists, along parallel tracks, have been trying to transform lignocellulosic biomass into biofuels. The work on second-generation biofuels (biofuels derived from lignocellulosic biomass rather than from grains, as in first-generation biofuel) has attracted billions of United States dollars in investment during the past two decades and yielded some impressive gains. Work by scientists in ILRI’s Feed and Forage Development program has recently brought those two strands of research together, by leveraging spin-offs from second generation biofuel technologies to upgrade animal feeding. In essence, biofuel scientists developed novel ways and processes of splitting off the glucose in the plant cell walls to convert it into ethanol, processes that ILRI leverages to improve fodder for animals.

The work on second-generation biofuels has attracted billions of United States dollars in investment during the past two decades and yielded some impressive gains.

ILRI and partner organizations recently explored the potential of leveraging three very different types of second-generation biofuel technologies on the fodder quality of a wide range of Indian cereal straws and stovers. (Straws are the dry stalks of fine grain crops such as rice, wheat and teff after their grain and chaff have been removed; stovers are the same, but from coarse grain plants such as maize, millet and sorghum.) One technology shows exceptional promise: the IICT 2-Chemical Combination Treatment (2CCT), which, as the name suggests, uses a combination of two chemical processes to break down the bonds holding the glucose to the lignin. The 2CCT brought the in vitro digestibility—a measurement of how much an animal can use of a feed—up from 56% to 94%, meaning that it rendered straw and stover almost completely digestible. Sheep fed on 2CCT-treated rice straw increased their weight gain by 3.7 times compared to animals fed untreated rice straw.

Spin-offs

These spin-off technologies are too complex to be applied directly by the farmers themselves. Rather, they will need to be embedded within private sector feed production. We view this as an advantage, however, and as a potential win-win situation. First, it will increase the availability of affordable farm-produced feed, which is desperately needed for increasing livestock productivity. Second, medium- and small-feed enterprises can become engaged in upgrading the fodder quality of straw and stover, generating rural income and employment opportunities. Finally, the technology may provide a way for farmers in specific areas of the Indo-Gangetic Plain to dispose of rice straw without burning it—with a concomitant reduction in the air pollution that is currently afflicting many Indian cities. The project is moving into the pilot stage now, with two commercially viable pilot reactors to be established in India.