The role of a novel fungal strain Trichoderma atroviride RVF3 in improving humic acid content in mature compost and vermicompost via ligninolytic and celluloxylanolytic activities.

AIMS: With the rising concerns about indiscriminate use of chemical fertilizers and accumulation of agro-industrial wastes in huge quantities, the present experiment was conducted to elucidate the effect of a novel fungal strain of Trichoderma atroviride in hastening the compost/vermicompost production process and for the production of humic acid (HA) rich compost and vermicompost. METHODS AND RESULTS: Rice (Oryza sativa) straw and distillation waste of geranium (Pelargonium graveolens), two important agricultural/industrial crop wastes were subjected to composting and vermicomposting. T. atroviride strains GVF10 (cellulase and xylanase producing), and RVF3 (ligninase and celluloxylanase producing) were inoculated alone or in combination. The HA content was found to increase maximally in rice vermicompost treated with ligninase producing strain RVF3 (85% with respect to HA standard) followed by geranium vermicompost + RVF3. The addition of the strain GVF10 increased HA content to about 35-62% with respect to HA standard. The addition of the fungal inoculum reduced the composting/vermicomposting time from 110 to 90 days. CONCLUSIONS: Our results indicate that the use of selected fungal strain(s) hold potential to produce qualitatively superior compost and vermicompost with high HA content in a shorter period. SIGNIFICANCE AND IMPACT OF THE STUDY: Use of appropriate fungal strains may increase the efficiency of composting/vermicomposting processes producing compost and vermicompost with higher HA content, and alleviating the problems of solid waste accumulation and declining soil fertility.

Tobacco consumption practices and risk of oro-pharyngeal cancer: a case-control study in Central India.

A hospital based, group matched case control study was conducted with the objective to assess the association between tobacco consumption practices and risk of development of oro-pharyngeal cancer in Central India. The study included 123 cases of oro-pharyngeal cancer, diagnosed on the basis of histopathology at three tertiary care centers in Nagpur city. Each case was matched for age and sex with two hospital controls: one selected from non-cancer patients and another from patients having cancer of other sites. Tobacco chewing (OR=7.98, 95% CI 4.11-13.58) and tobacco smoking (OR=2.25, 95% CI 1.22-3.70) were found to be significantly associated with oro-pharyngeal cancer on unconditional multiple logistic regression analysis. Further analysis revealed a dose-response relationship between increasing frequency, duration and retention time of tobacco in mouth and risk of oro-pharyngeal cancer. Other risk factors which were also found to contribute significantly in the outcome of oro-pharyngeal cancer in the study population were: use of traditional/local substances (eg pan, betel nut, lime) with or without tobacco, use of tobacco containing material for teeth cleaning, type of smoking (eg bidi, chillum, cigarette) and outdoor occupations. High values of estimates of attributable risk percent (ARP) and population attributable risk percent (PARP) confirmed the positive impact of reduction or elimination of the tobacco consumption practices on reducing the risk of oro-pharyngeal cancer in the population of Central India.