As a uni­ver­si­ty fo­cused on us­ing re­search for the up­lift­ment of its com­mu­ni­ty, the Uni­ver­si­ty of the West In­dies (UWI), St Au­gus­tine, the pre­mier ter­tiary in­sti­tu­tion in the re­gion, pro­duc­ing world-class schol­ars, be­lieves sci­ence should be ac­ces­si­ble to the pub­lic. We of­fer this me­dia se­ries, UWI Sci­en­tists Speak, where our sci­en­tists, three of whom re­cent­ly re­ceived the high­est award of the na­tion–the Or­der of the Re­pub­lic of Trinidad and To­ba­go, will present some of their work.

This week, we hear from Prof Ja­yaraj Ja­yara­man, who dis­cuss­es the work of the De­part­ment of Life Sci­ences, Fac­ul­ty of Sci­ence and Tech­nol­o­gy, on the de­vel­op­ment of bios­tim­u­lants us­ing Sar­gas­sum sea­weed and its im­pact on agri­cul­ture.

Prof Ja­yara­man is a full Pro­fes­sor of Biotech­nol­o­gy and Plant-Mi­cro­bi­ol­o­gy at the De­part­ment of Life Sci­ences. He is a mem­ber of the Sar­gas­sum val­oriza­tion team along with PhD can­di­date Mr Omar Ali and Prof Adesh Ram­sub­hag.

—Prof Rose-Marie Belle An­toine, prin­ci­pal, UWISTA

Prof Ja­yaraj Ja­yara­man

The brown al­gal sea­weed Sar­gas­sum spp mul­ti­plies rapid­ly and forms dense free-float­ing rafts on the ocean’s sur­face. There has been a ram­pant pro­lif­er­a­tion of this sea­weed in re­cent times due to cli­mate change and pol­lu­tion, which is ad­verse­ly af­fect­ing the Caribbean re­gion. The large amounts of sea­weed bio­mass that wash up on the shores every year pose a ma­jor chal­lenge for the ho­tel and tourism sec­tors. It takes sig­nif­i­cant re­sources to clear the Sar­gas­sum off beach­es, and in most cas­es, the bio­mass is left to rot.

De­com­pos­ing Sar­gas­sum is not on­ly an eye­sore to vis­i­tors to the beach, but it al­so re­leas­es hy­dro­gen sul­phide and am­mo­nia, which can have se­ri­ous health ef­fects on hu­mans, an­i­mals, and the ecosys­tem.

The best strat­e­gy for deal­ing with the Sar­gas­sum prob­lem is to find suit­able us­es for bio­mass as a raw ma­te­r­i­al for in­dus­tries. On­go­ing re­search around the world on de­vel­op­ing val­ue-added prod­ucts from Sar­gas­sum has not yield­ed much trans­for­ma­tion from lab­o­ra­to­ries to in­dus­tries.

A team of re­searchers at the UWI, St Au­gus­tine’s De­part­ment of Life Sci­ences, has been work­ing on the Caribbean sea­weeds for more than a decade, main­ly to ex­am­ine their plant bios­tim­u­la­to­ry prop­er­ties.

The team’s fo­cus shift­ed to Sar­gas­sum since this sea­weed be­came a prob­lem about six years ago. The team com­pris­ing Prof Ja­yaraj Ja­yara­man (PI), Prof Adesh Ram­sub­hag (coPI), and Omar Ali (PhD stu­dent), along with sev­er­al stu­dents, have been lead­ing the re­search on Sar­gas­sum val­oriza­tion.

They de­vel­oped eco-friend­ly and en­er­gy-ef­fi­cient meth­ods of ex­tract­ing bios­tim­u­lant mol­e­cules from the dried sea­weed bio­mass. The ex­trac­tion meth­ods yield a com­bi­na­tion of bioac­tive mol­e­cules that are very as­sim­i­l­able to plants but al­so safe for the en­vi­ron­ment. The over­all aim of the team is to min­imise the use of agro­chem­i­cals in farm­ing and sub­sti­tute them with safe bi­o­log­i­cal in­puts. The sta­ble Sar­gas­sum-ex­tract-based for­mu­la­tion de­vel­oped will pro­vide farm­ers with a good op­tion as an or­gan­ic-based bios­tim­u­lant for re­duc­ing the need for syn­thet­ic chem­i­cals.

The stud­ies thus far re­vealed mul­ti­ple ben­e­fi­cial ef­fects of the Sar­gas­sum ex­tracts and for­mu­la­tions on plants and the ecosys­tem. The ex­tracts con­tain sev­er­al mir­a­cle mol­e­cules that act as trig­gers for en­hanc­ing plant growth and de­fence against pests and dis­eases and pro­mot­ing tol­er­ance to abi­ot­ic stress con­di­tions. Crops treat­ed with Sar­gas­sum ex­tracts in the field gave 50-70 per cent high­er yield on av­er­age as com­pared to con­trols. The qual­i­ty of the pro­duce al­so im­proved, eg, big­ger fruits, bet­ter nu­tri­tion­al con­tents, less post-har­vest dam­age, and im­proved mar­ket qual­i­ty.

To re­veal the mech­a­nisms of ac­tion of the ex­tracts, the team em­ployed con­tem­po­rary cut­ting-edge gene ex­pres­sion stud­ies that in­ter­est­ing­ly showed the up­reg­u­la­tion of mul­ti­ple path­ways in­volved in plant meta­bol­ic process­es syn­chro­nous­ly and har­mon­i­cal­ly that con­tributed to in­creased growth and pro­duc­tiv­i­ty, dis­ease sup­pres­sion and re­silience to abi­ot­ic stress. Sev­er­al genes re­spon­si­ble for flow­er­ing were al­so up-reg­u­lat­ed for a longer du­ra­tion, ex­plain­ing the high­er rate of flow­er­ing, flower-fruit num­ber, and ex­tend­ed pro­duc­tive phase of Sar­gas­sum ex­tract-treat­ed plants.

Un­der field con­di­tions, the dam­age caused by dis­eases, in­clud­ing those by virus­es, was re­duced by at least 50 per cent through fo­liar sprays with Sar­gas­sum ex­tract every two weeks.

On a prac­ti­cal ba­sis, the team demon­strat­ed high­er yields with min­i­mum ap­pli­ca­tion of gener­ic pes­ti­cides while us­ing Sar­gas­sum ex­tract and oth­er bi­o­log­i­cal in­puts in a suc­cess­ful in­te­grat­ed pest and dis­ease man­age­ment sys­tem. By in­clud­ing the Sar­gas­sum ex­tract for­mu­la­tion in the spray sched­ule, it was pos­si­ble to re­duce fungi­cide ap­pli­ca­tion fre­quen­cy by more than 50 per cent while achiev­ing bet­ter yields.

One hid­den phe­nom­e­non of­ten over­looked is the im­pact of bi­o­log­i­cal in­puts on the plant and soil mi­cro­bial com­mu­ni­ties, which play a ma­jor role in con­di­tion­ing plant growth and main­tain­ing equi­lib­ri­um with the ecosys­tem.

These ex­cit­ing re­sults have con­firmed the pos­i­tive ef­fects of the Sar­gas­sum ex­tracts on en­hanc­ing the ac­tiv­i­ty of ben­e­fi­cial mi­croor­gan­isms, both in­ter­nal­ly and on the plant’s ex­ter­nal sur­faces.

The sta­ble for­mu­la­tion de­vel­oped by the UWI re­searchers is cur­rent­ly in the fi­nal stages of eval­u­a­tion to­wards com­mer­cial­i­sa­tion. They have al­so ini­ti­at­ed re­search us­ing bulk Sar­gas­sum bio­mass for de­vel­op­ing en­riched com­posts and bioac­ti­vat­ed ma­nures with ac­cept­able lev­els of heavy met­als. Most of the stud­ies have been with veg­etable crops, but work has now start­ed with tu­bers, grains, and fruit crops.

The team’s re­search on sea­weed ex­tracts has been well-pub­lished and well-cit­ed with­in the sci­en­tif­ic com­mu­ni­ty. Con­se­quent­ly, they are a lead­ing group in the Caribbean and South Amer­i­ca on sea­weed bioelic­i­tor re­search and were able to col­lab­o­rate suc­cess­ful­ly with re­searchers around the world. Re­cent­ly, they have de­vel­oped part­ner­ships through the France/EDF-fund­ed IN­TER­REG-SAR­GOOD project, which fa­cil­i­tat­ed re­search col­lab­o­ra­tion in the re­gion.