Using biotechnology to develop new uses for sugar-cane bagasse

Interested in biotechnology or the use of alternative fibres? An article published in TAPPSA reports on a non-polluting process, using a filamentous fungus, Pycnoporus cinnabarinus, which produces a delignifying enzyme, laccase, that effectively recycles the sugar-cane bagasse. The enzyme breaks down the lignin in the bagasse fibres and, after mechanical refining, into paper pulp, the lignin starts to disappear and the pulp becomes 'bleached'. This pulp can be used as it is to make cardboard, but it must undergo additional treatment using hydrogen peroxide in order to yield paper for printed and writing papers.

P. cinnabarinus naturally synthesizes only small amounts of laccase when it grows on bagasse and it is necessary to add a volatile agent such as ethanol, to increase production of the enzyme. Ethanol was chosen as a laccase-inducer because of its abundance, its low toxicity and low production cost.

Early days but another step on the road to using laccases. There may be fears of using volatile solvents in pulp mills because of some disastrous experiences in the past, but it should be possible to handle ethanol on an industrial scale.

The work was reported by Marie Guillaume-Signoret – Institut de Recherche Pour le Développement (IRD).