Marine cyanobacterial biomass is an efficient feedstock for fungal bioprocesses.

BACKGROUND: Marine cyanobacteria offer many sustainability advantages, such as the ability to fix atmospheric CO2, very fast growth and no dependence on freshwater for culture. Cyanobacterial biomass is a rich source of sugars and proteins, two essential nutrients for culturing any heterotroph. However, no previous study has evaluated their application as a feedstock for fungal bioprocesses. RESULTS: In this work, we cultured the marine cyanobacterium Synechococcus sp. PCC 7002 in a 3-L externally illuminated bioreactor with working volume of 2 L with a biomass productivity of ~ 0.8 g L-1 day-1. Hydrolysis of the biomass with acids released proteins and hydrolyzed glycogen while hydrolysis of the biomass with base released only proteins but did not hydrolyze glycogen. Among the different acids tested, treatment with HNO3 led to the highest release of proteins and glucose. Cyanobacterial biomass hydrolysate (CBH) prepared in HNO3 was used as a medium to produce cellulase enzyme by the Penicillium funiculosum OAO3 strain while CBH prepared in HCl and treated with charcoal was used as a medium for citric acid by Aspergillus tubingensis. Approximately 50% higher titers of both products were obtained compared to traditional media. CONCLUSIONS: These results show that the hydrolysate of marine cyanobacteria is an effective source of nutrients/proteins for fungal bioprocesses.

Solid state bioconversion of wheat straw into digestible and nutritive ruminant feed by Ganoderma sp. rckk02.

Solid state fermentation (SSF) of wheat straw with Ganoderma sp. rckk02 was carried out for 15 days for improving its digestibility and nutrients. Fungal growth caused a significant (P<0.05) decrease in acid detergent fiber (ADF), neutral detergent fiber (NDF), hemicellulose, lignin and cellulose content till 15th day. In vitro gas production (IVGP) test revealed that 10th day fermented feed possessed higher metabolizable energy (ME: 4.87 MJ/kg), in vitro organic matter digestibility (OMD: 334 g/kg) and short chain fatty acids (SCFAs: 1.82 mmol/g Dry Matter). The fermented feed was also evaluated in vivo in goats fed with either untreated wheat straw (T1) or fungal treated straw (T2). Dry matter intake (DMI), digestible crude protein (DCP), total digestible nutrients (TDN) and nitrogen (N) intake were found significantly (P<0.05) increased in T2 group. The study shows that fermentation of wheat straw with Ganoderma sp. rckk02 holds potential in improving its nutritive value.