Bioprospecting of thermo- and osmo-tolerant fungi from mango pulp-peel compost for bioethanol production.

The persistent edaphic stress on microbial succession due to dynamic changes during composting was explored for selection of multi-stress tolerant microbe(s) desirable for ethanol production. A total of 23 strains were isolated from mango compost using four successive enrichments in YP broth (g l(-1)): glucose, 100; 150; 250 with ethanol (40) and cycloheximide (0.4) at 40 °C, pH 6.0. Based on multi-gene ribotyping, 14 yeasts (61 %) of Saccharomycetaceae, 2 filamentous fungi (8.6 %) and 7 bacteria (30.4 %) were obtained. Phenetic and phylogenetic analysis of the 14 yeasts revealed 64.3 % tolerant to 500 g l(-1) glucose, growth at 45 °C and resemblance to Candida sp. (14.3 %), Kluyveromyces marxianus (35.7 %), Pichia kudriavzevii (21.4 %) and Saccharomyces cerevisiae (28.6 %). Assessment of the 14 yeasts in glucose fermentation medium (pH 4.5 at 40 °C) showed ethanol productivity of ≥92 % by 12 yeasts with theoretical yields of 90-97 %. Fermentation of molasses (150 g l(-1) glucose equivalent) by P. kudriavzevii D1C at 40 °C resulted in 73.70 ± 0.02 g l(-1) ethanol and productivity of 4.91 ± 0.01 g l(-1) h(-1). Assessment of P. kudriavzevii D1C revealed multi-stress tolerance towards 5-hydroxymethyl furfural, ethanol (20 %, v/v), high gravity and H2O2 (0.3 M) indicating suitability for ethanol production using high gravity molasses and pre-treated lignocellulosic biomass fermentation.

Bioconversion of renewable resources into lactic acid: an industrial view.

Lactic acid, an anaerobic product of glycolysis, can be theoretically produced by synthetic route; however, it is commercially produced by homo-fermentative batch mode of operations. Factors affecting its production and strategies improving it are considered while devising an optimized protocol. Although a hetero-fermentative mode of production exists, it is rarely used for commercial production. Attempts to use Rhizopus sp. for lactic acid production through either hetero-fermentative or thermophilic conditions were not economical. Since almost 70% of the cost of its production is accounted by raw materials, R & D efforts are still focused to find economically attractive agri-products to serve as sources of carbon and complex nitrogen inputs to meet fastidious nutrient needs for microbial growth and lactic acid production. Therefore, need exists for using multi-pronged strategies for higher productivity. Its present production and consumption scenario is examined. Its optically active isomers and chemical structure permit its use for the production of several industrially important chemicals, health products (probiotics), food preservatives, and bio-plastics. In addition, its salts and esters appear to have a variety of applications.

Mesophilic anaerobic digestion: first option for waste treatment in tropical regions.

Rural India derives its energy needs for cooking and heating through the use of fuel wood and for lighting and agricultural operations through kerosene and diesel. Use of fuel wood has aggravated the problem of de-forestation, while availability of kerosene and diesel cannot be guaranteed due to corrupt practices in the public distribution systems. In contrast, urban India derives its energy needs through LPG cylinders, petrol, and electricity. However, their cost and uncertainty rendered them beyond the reach of lower income population. This scenario is more or less true with many developing countries. To meet these objectives, biogas generation from biodegradable waste using anaerobic digestion (AD) appears to be a sustainable avenue as it could be used for (a) water and space heating of farmhouses, animal shelters, (b) generating steam for food processing plants, and (c) electricity generation, in addition to reducing the pollution/hazard potential of these wastes. Many of the underdeveloped and developing countries are in the temperate zone and thus mesophilic AD could provide a desired pathway to achieve a long delayed need of energy for comfortable living, farming, and industrial operations. Efforts made in this direction are reviewed in the present article.

Thermophilic anaerobic digestion: the best option for waste treatment.

After introducing thermophilic anaerobic digestion (AD), characteristics of thermophilic methanogens are provided. Accordingly, (a) site of occurrence, (b) morphological characteristics (shape and motility), (c) biochemical characteristics (Gram character and % G+C profile), (d) nutritional characteristics (NaCl requirement and substrate specificity), and (e) growth characteristics (pH and temperature) of thermophilic methanogens are described. Some studies of the thermophilic AD are cited with their operational management problems. Subsequently, strategies to maximize net energy production are given, including mode of heating the bioreactors, role of agitation to promote AD performance and mode/intensity of mixing. Finally, advantages as well as drawbacks of AD under thermophilic conditions are given, concluding with its applications.

Solid state cultivation of Curvularia lunata for transformation of rifamycin B to S.

Biotransformation of rifamycin B to rifamycin S using two strains of C. lunata namely NCIM 716 and NMU grown on various solid substrates viz., grass, paper, jowar/wheat straw, bran and bagasse was studied. Almost complete biotransformation efficiency of rifamycin B at 0. 06 mM concentration was observed within 24 hr. Among these two strains, C. lunata NMU showed 90% of biotransformation and higher rate of cellulose utilization on solid substrates vis-à-vis reference strain. Cellulase activity of both strains was also studied for exoglucanase, endoglucanase and beta-glucosidase. Column bioreactor studies with bagasse revealed further improvement in biotransformation efficiency of C. lunata NMU.

Subdural empyema--an unusual presentation. A report on 2 cases.

Two cases of subdural empyema with unusual clinical features are described. Both had an undetermined primary source of infection, the onset was insidious and the course was rather indolent, and both cases occurred after steroid therapy. Subdural empyema is a potentially lethal condition if inappropriately managed. A high index of suspicion and prompt definitive treatment remain the cornerstones of successful management. The aetiology and pathogenesis of subdural empyema and the merits and demerits of various investigative procedures are discussed; the factors that influence prognosis are highlighted.

Haemorrhage in cerebral toxoplasmosis. A report on a patient with the acquired immunodeficiency syndrome.

A patient with the acquired immunodeficiency syndrome (AIDS) presented to hospital with a haemorrhagic cerebral lesion. The lesion was biopsied and electron microscopy confirmed a diagnosis of toxoplasmosis. Although known in congenital cases, haemorrhagic infarction is unknown in adults suffering from cerebral toxoplasmosis. Severe vasculitis with subsequent thrombosis and extensive fibrinoid necrosis of the vessel wall or direct parasitism of endothelial cells with subsequent destruction and seepage of blood appear to be the possible mechanisms in a situation where the T-cell immune mechanism and tissue cell response are compromised. Other intracerebral haemorrhagic lesions in AIDS were reviewed.

Congenital inclusion cysts of the subgaleal space.

Congenital inclusion cysts of the subgaleal space in 23 white children are reported. Twenty-two cysts were dermoid and one was epidermoid in nature. The lesions were extracranial and had no intracranial extension. Their location in the subgaleal space was median or paramedian. Their clinical, radiologic, biochemical, and histologic characteristics are detailed and compared with those from Africa. This series counters the motion that such cysts are extremely rare in whites and that the anterior fontanel is their only site of location, as claimed by various authors from Africa.

Congenital inclusion cyst of the subgaleal space.

An unusual type of congenital subgaleal cyst, either dermoid or epidermoid, was found in 21 Nigerian infants. This entity was located in the midline of the scalp, anywhere from above the nasion to the inion, and occupied the subgaleal space. These cysts were noted soon after birth and gradually enlarged. They had no intracranial extension and were easily excised intact. Clinically, radiologically, and histologically they were similar to congenital inclusion dermoid cysts of the anterior fontanel. The histology and some of the peculiarities of these cysts are described. Although most of these cysts occur at the anterior fontanel, they can occur anywhere in the midline, and the subgaleal space of the anterior fontanel is not the exclusive site, as has been claimed by previous authors.

Fibrosarcoma of the scalp. Case report.

A parieto-occipital scalp tumor, noted in a Nigerian boy during the first month of his life, gradually increased in size, and after two attempts at partial removal there was a rapid increase in its size. When he was 17 years old, it measured 21 X 17 X 16 cm. There was no underlying skull defect. Complete excision of the tumor was achieved, and on histological examination it was found to be a fibrosarcoma. The patient was given a course of radiotherapy following wound healing. He remained well for 5 1/2 months but then had manifestations of small local recurrence and distant metastases that responded only minimally to another course of radiotherapy combined with cancer chemotherapy.

Giant cell tumor of the sphenoid bone.

The clinical and histological features of two cases of giant cell tumor of the sphenoid bone are described. Both presented with similar symptoms and signs, comparable to previously described cases. The problems in histological differential diagnosis are discussed and radiotherapy as the treatment of choice is suggested.