Effective methane production from the Japanese weed Gyougi-shiba (Cynodon dactylon) is accomplished by colocalization of microbial communities that assimilate water-soluble and -insoluble fractions.

Weed, an abundant biomass, is considered unsuitable as a raw material for methane production. There are few reports on the anaerobic digestion of weeds without the addition of other organic wastes. To solve this problem, a methane-producing microbial community with weed as a sole feedstock was established. This study mainly focused on the degree of contribution between water-soluble and -insoluble fractions of the weed to methane production; thus, methane production from both fractions was tested separately. Methane production after 80-day batch cultures with whole weed, water-soluble and water-insoluble fractions was 184.5, 96.8 and 26.5 NmL g-1 dry matter (DM), respectively. The results of 16S rRNA gene amplicon sequence analysis revealed that Proteiniphilum saccharofermentans and several Methanobacterium species commonly dominated all cultures, whereas the population dynamics of minor species differed in every culture. Moreover, the remixed culture of microbial communities adapted to water-soluble and -insoluble fractions recovered methane production (252.4 NmL g-1 DM). Based on these results, it can be strongly inferred that colocalizing the minor species in water-soluble and -insoluble fractions is important for effective methane production.

Enhanced inulinase production by Fusarium solani JALPK from invasive weed using response surface methodology.

The present study is the first report of utilizing Tithonia rotundifolia weed as a substrate for inulinase production from Fusarium solani JALPK. It also deals with the statistical optimization of culture conditions to enhance the enzyme yield. Amongst the 11 variables screened by Plackett- Burman design, Inulin in combination with Agave sisalana extract, Tithonia rotundifolia extract and NaNO3 had a significant influence on inulinase production and their concentrations were further optimized employing Box Behnken design. An enhancement of inulinase production from 970 EU/mL to 3261.011 EU/mL was gained after media optimization. Amongst the screened carbon sources Tithonia rotundifolia was found to be very effective in stimulating elevated inulinase synthesis. The Tithonia rotundifolia weed extract was treated with inulinase from Fusarium solani JALPK to form fructose which was estimated spectrophotometrically. This liberated fructose was also confirmed by osazone formation test and FTIR. HPTLC analysis of product revealed the exoinulinase nature of the enzyme produced by Fusarium solani JALPK since fructose was the only end product after hydrolysis of inulin rich weed in fermented broth. Thus the elevated extracellular inulinase yielding novel property of Fusarium solani JALPK (KY914560) contributes in considering it as a potential candidate with food, pharmaceutical and bioremediation applications.