Commercial oil-yielding seeds (castor, coconut, neem, peanut, pongamia, rubber and sesame) were collected from different places in the state of Tamil Nadu (India) from which 1279 endophytic fungi were isolated. The oil-bearing seeds exhibited rich fungal diversity. High Shannon-Index H' was observed with pongamia seeds (2.847) while a low Index occurred for coconut kernel-associated mycoflora (1.018). Maximum Colonization Frequency (%) was observed for Lasiodiplodia theobromae (176). Dominance Index (expressed in terms of the Simpson's Index D) was high (0.581) for coconut kernel-associated fungi, and low for pongamia seed-borne fungi. Species Richness (Chao) of the fungal isolates was high (47.09) in the case of neem seeds, and low (16.6) for peanut seeds. All 1279 fungal isolates were screened for lipolytic activity employing a zymogram method using Tween-20 in agar. Forty isolates showed strong lipolytic activity, and were morphologically identified as belonging to 19 taxa (Alternaria, Aspergillus, Chalaropsis, Cladosporium, Colletotrichum, Curvularia, Drechslera, Fusarium, Lasiodiplodia, Mucor, Penicillium, Pestalotiopsis, Phoma, Phomopsis, Phyllosticta, Rhizopus, Sclerotinia, Stachybotrys and Trichoderma). These isolates also exhibited amylolytic, proteolytic and cellulolytic activities. Five fungal isolates (Aspergillus niger, Chalaropsis thielavioides, Colletotrichum gloeosporioides, Lasiodiplodia theobromae and Phoma glomerata) exhibited highest lipase activities, and the best producer was Lasiodiplodia theobromae (108 U/mL), which was characterized by genomic sequence analysis of the ITS region of 18S rDNA.

The coconut kernel-associated fungus, Lasiodiplodia theobromae VBE1, was grown on coconut cake with added coconut oil as lipase inducer under solid-state fermentation conditions. The extracellular-produced lipases were purified and resulted in two enzymes: lipase A (68,000 Da)-purified 25.41-fold, recovery of 47.1%-and lipase B (32,000 Da)-purified 18.47-fold, recovery of 8.2%. Both lipases showed optimal activity at pH 8.0 and 35 °C, were activated by Ca, exhibited highest specificity towards coconut oil and p-nitrophenyl palmitate, and were stable in iso-octane and hexane. Ethanol supported higher lipase activity than methanol, and n-butanol inactivated both lipases. Crude lipase immobilized by entrapment within 4% (w/v) calcium alginate beads was more stable than the crude-free lipase preparation within the range pH 2.5-10.0 and 20-80 °C. The immobilized lipase preparation was used to catalyze the transesterification/methanolysis of coconut oil to biodiesel (fatty acyl methyl esters (FAMEs)) and was quantified by gas chromatography. The principal FAMEs were laurate (46.1%), myristate (22.3%), palmitate (9.9%), and oleate (7.2%), with minor amounts of caprylate, caprate, and stearate also present. The FAME profile was comparatively similar to NaOH-mediated transesterified biodiesel from coconut oil, but distinctly different to petroleum-derived diesel. This study concluded that Lasiodiplodia theobromae VBE1 lipases have potential for biodiesel production from coconut oil.

Plant oil-extracted seed-cakes are good fermentation substrates for producing lipases that find application in transesterification of seed oils into biodiesel. This work describes the production of lipases by five lipolytic, oil-seed associated fungi (Aspergillus niger, Chalaropsis thielavioides, Colletotrichum gloeosporioides, Lasiodiplodia theobromae, and Phoma glomerata) by Solid-State Fermentation (SSF) on eight plant oil-seed cakes. The highest lipase activity was from the Coelomycete Lasiodiplodia theobromae VBE-1 grown on coconut kernel-cake, and was selected to optimize lipase production. The effects of supplementing coconut kernel-cake with mineral salts and coconut oil on lipase production by L. theobromae VBE-1 resulted in enhanced lipase activity. The effects of time of growth, moisture content, initial pH, temperature, as well as nutritional factors (carbon, nitrogen, vegetable oils, surfactants) when added to coconut kernel-cake, on lipase production were examined by a onefactor-at-a-time approach, and identified key variables for optimization by Response Surface Methodology (RSM). A 2 6 factorial central-composite experimental design with eight starting points and six replicates at the central point was used for lipase optimization. After validating the predicted levels of the factors, lipase production rose to 698 U/g Dry Substrate (DS) over un-optimized conditions (450 U/g DS).